Danfoss MCE 101 Design guide

ENGINEERING TOMORROW

Design Guide

VLT® Brake Resistor MCE 101

VLT® AutomationDrive FC 360

vlt-drives.danfoss.com

Contents Design Guide

Contents

1 Introduction

1.1 Purpose of the Manual

1.2 Conformity

1.3 Safety Precautions

1.4 Disposal

2 Product Overview

2.1 Description of the Brake System

2.2 Horizontal or Vertical Load

2.2.1 How to Select 5

2.3 Aluminum-housed Brake Resistors

2.3.1 Aluminum-housed Flat-pack Brake Resistors 5

2.3.2 Aluminum-housed Compact Brake Resistor 6

2.4 Steel Grid Brake Resistors

3 Installation

3.1 Mechanical Installation

3.1.1 Aluminum-housed Compact Brake Resistors and Flat-pack Brake Resistors 7

3.1.2 Steel Grid Brake Resistors 10

3.1.3 Accessories 11

3.2 Electrical Installation

3.2.1 EMC Precautions 12

3.2.2 Cable Connection 13

3.2.3 Brake Cable 13

3.3 Protective Functions

3.3.1 Overtemperature Protection 13

3.3.2 Brake Resistor and Brake IGBT 15

4 System Integration

4.1 Brake Resistor Calculation

4.1.1 Brake Set-up 16

4.1.2 Calculation of Brake Resistor Resistance 16

4.1.3 Calculation of Braking Power 17

4.1.4 Calculation of the Brake Resistor Peak Power 17

4.1.5 Calculation of the Brake Resistor Average Power 17

4.1.6 Braking of Inertia 18

5 Parameters

6 Application Examples

6.1 Conveyor Belt

Contents

VLT® Brake Resistor MCE 101

6.2 Centrifuge

6.3 Continuous Braking

7 Special Conditions

7.1 Alternative Braking Methods

7.1.1 DC Injection Braking 24

7.1.2 AC-braking 24

7.1.3 Mechanical Holding Brake 24

7.1.4 DC Braking 24

8 Selection Guide

8.1 Selection Flow Chart

8.2 Selection Tables for Recommended Brake Resistors

8.2.1 Abbreviations used in the Brake Resistor Tables 26

8.2.2 VLT® AutomationDrive FC 360 26

9 Specications

9.1 Ambient Conditions

9.2 General Electrical Specications

9.3 Electrical Data: MCE 101 Product Types 9xx

9.4 Mechanical Data: MCE 101 Product Types 9xx

9.5 Electrical Data: Product Types BWD and BWG

9.6 Mechanical Data: Product Types BWD and BWG

9.7 Mechanical Drawings

9.7.1 Figure 1 - 914CBT-HxxxDHT 54

9.7.2 Figure 2 - 914CBT-HxxxCHT 58

9.7.3 Figure 3 - 914CBT-HxxxBHT 61

9.7.4 Figure 4 - 914CBR-VxxxDT 64

9.7.5 Figure 5 - 914CBR-VxxxCT 67

9.7.6 Figure 6 - 914CBR-VxxxBT 69

9.7.7 Figure 7 - 914CCHxxxCT 72

9.7.8 Figure 8 - 917CM13 74

9.7.9 Figure 9 - 917CM15 76

9.7.10 Figure 10 - 917CM17 78

9.7.11 Figure 11 - 917CM25 80

9.7.12 Figure 12 - 917CM27 82

9.7.13 Figure 13 - 917CM37 84

9.7.14 Figure 14 - 917CMD27 86

9.7.15 Figure 15 - 917CMD37 88

9.7.16 Figure 16 - 929CBT-VxxxGHT 90

9.7.17 Figure 17 - 929CBT-VxxxBGHT 93

Contents Design Guide

9.7.18 Figure 18 - 930CBT-VxxxGHT 96

9.7.19 Figure 19 - 930CBT- VxxxBGHT 99

9.7.20 Figure 20 - BWD250xxx 102

9.7.21 Figure 21 - BWD500xxx 103

9.7.22 Figure 22 - BWD600xxx 104

9.7.23 Figure 23 - BWG250xxx 105

9.7.24 Figure 24 - BWG500xxx 106

9.8 Mechanical Drawings: Accessories

9.8.1 Mounting Brackets: L Prole 107

9.8.2 Mounting Brackets: Footprint 109

Index

107

112

Introduction

VLT® Brake Resistor MCE 101

1 Introduction

1.1 Purpose of the Manual

The design guide provides the information required to select and plan installation of the right brake resistor for an application:

Selection of the correct brake resistor.

•

Pre-installation considerations.

•

Programming.

•

As an alternative to using a brake resistor, other braking methods can be applied depending on the braking prole of the application, see chapter 7 Special Conditions.

More technical literature is also available online at

drives.danfoss.com/knowledge-center/technical-documentation/.

1.2 Conformity

Safety Precautions

1.3

WARNING

SURFACE TEMPERATURE

When in use, the brake resistor surface temperature rises.

DO NOT touch the brake resistor during

•

operation.

WARNING

HAZARD DURING OPERATION

Work on a brake resistor in operation can result in serious injury.

Never work on a brake resistor in operation.

•

Ensure that only trained and qualied personnel

•

can work on a brake resistor.

Table 1.1 Approval

1) See Table 9.2 and Table 9.4 for UL conformity.

What is CE conformity and labeling

The purpose of CE labeling is to avoid technical trade obstacles within EFTA and the EU. The EU has introduced the CE label as a simple way of showing whether a product complies with the relevant EU directives. The CE label says nothing about the the product. Brake resistors are regulated by the following EU directive:

The Low Voltage Directive (2014/35/EU)

Brake resistors must be CE labeled in accordance with the Low Voltage Directive of April 20, 2016. The directive applies to all electrical equipment and appliances used in the 50–1000 V AC and the 75–1500 V DC voltage ranges. Danfoss CE-labels in accordance with the directive and issues a declaration of conformity after request.

specications or quality of

NOTICE

Never attempt to repair a defective brake resistor.

1.4 Disposal

Equipment containing electrical components

may not be disposed of together with

domestic waste.

It must be separately collected with electrical

and electronic waste according to local and

currently valid legislation.

150/160%

175UA067.10

100%

150/160%

175UA068.10

130BD245.12

Product Overview Design Guide

2 Product Overview

2.1 Description of the Brake System

When the speed reference of a frequency converter is reduced, the motor acts as a generator and the frequency converter brakes. When a motor acts as a generator, it supplies energy to the frequency converter which is collected in the DC link. The function of the brake resistor is to provide a load on the DC link during braking, thereby ensuring that the braking power is absorbed by the brake resistor.

If a brake resistor is not used, the DC-link voltage of the frequency converter continues to increase, until disconnecting for protection. The advantage of using a brake resistor is that it enables braking of a heavy load quickly, for example on a conveyor belt.

2 2

Illustration 2.2 Vertical Loads

The brake resistor range is intended to cover the general braking requirements for horizontal and vertical brake applications. To select the best brake resistor for an application, refer to chapter 8.1 Selection Flow Chart. The ow chart links to further information, either selection tables or calculations of inertia or duty cycle.

The brake resistors in this series are all external components. Therefore, the brake resistor does not form an integral part of the frequency converter.

The external brake resistor provides the following advantages:

The resistor time cycle can be selected as

•

required.

The heat developed during braking can be

•

conveyed beyond the panel cabinet to allow the energy to be used.

The electronic components do not overheat, even

•

when the brake resistor is overloaded.

Horizontal or Vertical Load

2.2

2.2.1 How to Select

The Danfoss brake resistor range consists of 2 groups:

Brake resistors for horizontal loads (conveyors,

•

trolleys, gantry cranes, and so on), see Illustration 2.1;

Brake resistors for vertical loads (cranes, hoists,

•

elevators), see Illustration 2.2.

To cater for both the horizontal and vertical ranges, 3 types of brake resistors are available:

Aluminum-housed at-pack brake resistors.

•

Aluminum-housed compact brake resistors.

•

Steel grid brake resistors.

•

Aluminum-housed Brake Resistors

2.3

2.3.1 Aluminum-housed Flat-pack Brake Resistors

The at-pack brake resistor is an anodized aluminumhoused resistor suitable for wall mounting or on a footprint or an L-prole bracket. The L-prole bracket is used for rear mounting. The brake resistor is designed for high pulse loads of up to 40 times the nominal load and is therefore suitable for both vertical and horizontal applications. The enclosure protection is IP54 or IP65.

Illustration 2.3 Flat-pack IP54

Illustration 2.1 Horizontal Loads

130BD646.10

130BD228.10

130BD217.10

130BD586.10

Product Overview

VLT® Brake Resistor MCE 101

2.3.2 Aluminum-housed Compact Brake

2.4 Steel Grid Brake Resistors

Resistor

The steel grid brake resistor is steel grid housed and

The compact brake resistor is housed in aluminum proles with pre-mounted brackets for wall mount. It is designed for high pulse loads of up to 60 times the nominal load and is therefore used for both horizontal and vertical loads. The enclosure protection class is either IP21, IP54, or IP65. The brake resistor IP classes IP21 and IP65 are equipped with a connection box containing cable glands and cable connection to the resistor and the temperature switch. IP54 versions have xed unshielded cables.

Illustration 2.4 CBR-V-CT IP54

consists of multiple elements. This brake resistor is suitable for pulse loads between 10 and 20 times the nominal load, suitable for frequent braking applications such as cranes, hoists, and elevators. It is supplied in an IP20 enclosure with cable glands and has a built-in temperature switch.

Illustration 2.5 CBR-V-DT IP21

Illustration 2.7 Steel Grid House IP20

Illustration 2.6 CBR-V-BT IP65

130BD900.10

200 mm

Installation Design Guide

3 Installation

3.1 Mechanical Installation

The brake resistors are cooled by natural convection, and the specied minimum clearances must be observed to ensure ecient ventilation. The ventilation must be ecient enough to dispatch the regenerative power in the brake resistor.

NOTICE

When installing the brake resistor, ensure that all precautions are in place to avoid the risk of overloading. Overloading can lead to a re hazard due to the heat generated in the brake resistor. The brake resistor is hot during or after braking. The brake resistor must be located in a secure environment to avoid re risk.

Mount the brake resistor free of any combustible

•

materials at a well-ventilated location.

The VLT® Brake Resistors MCE 101 brake resistors

•

product type 9xx contain a built-in temperature switch (for overtemperature protection purposes. See chapter 3.3 Protective Functions).

3.1.1 Aluminum-housed Compact Brake Resistors and Flat-pack Brake Resistors

3 3

Illustration 3.1 Vertical Mounting, IP54

Versions with Fixed Cables

The aluminum-housed compact and at-pack brake resistors are designed for vertical mounting for optimum cooling performance. However, horizontal mounting is possible for both at-pack and compact brake resistors. Derating with 20% is required when mounting the compact brake resistors horizontally. No derating for at- packs are required. The enclosure protection of the IP21 types is reduced to IP20 when mounted horizontally.

NOTICE

All resistors are cooled by natural convection. To ensure sucient airow and cooling, follow minimum clearance in Illustration 3.1 to Illustration 3.8.

Vertical mounting, IP54

For minimum clearances for vertical mounting for all aluminum-housed compact and at-pack brake resistors, see Illustration 3.1 and Illustration 3.2.

130BD901.10

200 mm

500 mm

200 mm

200 mm200 mm

130BD902.10

130BD903.10

500 mm

130BD904.10

200 mm

Installation

VLT® Brake Resistor MCE 101

For minimum clearances for horizontal mounting for all aluminum-housed compact and at-pack brake resistors, IP54 versions (versions with xed cables), see Illustration 3.4 (side view).

Illustration 3.4 Horizontal mounting, IP54

Versions with Fixed Cables

Vertical mounting, IP21 and IP65

For minimum clearances for vertical mounting for all aluminum-housed compact brake resistors, see Illustration 3.5 and Illustration 3.6.

Illustration 3.2 Vertical Mounting, IP54

Versions with Fixed Cables

Horizontal mounting, IP54

For minimum clearances for horizontal mounting for all aluminum-housed compact and at-pack brake resistors, see Illustration 3.3 (top view).

Illustration 3.3 Horizontal mounting, IP54

Versions with Fixed Cables

Illustration 3.5 Vertical Mounting, IP21 and IP65

Versions with Connection Box

200 mm

500 mm

100 mm

130BD905.10

200 mm

100 mm

200 mm

130BD906.10

130BD907.10

500 mm

Installation Design Guide

Horizontal mounting, IP21 and IP65

For minimum clearances for horizontal mounting for all aluminum-housed compact brake resistors, see Illustration 3.7 (top view).

3 3

Illustration 3.7 Horizontal Mounting, IP21 and IP65

Versions with Connection Box

Horizontal mounting, IP21 and IP65

For minimum clearances for horizontal mounting for all aluminum housed compact brake resistors, see Illustration 3.8 (side view).

Illustration 3.6 Vertical Mounting, IP21 and IP65

Versions with Connection Box

Illustration 3.8 Horizontal Mounting, IP21 and IP65

Versions with Connection Box

130BD227.11

130BD708.12

150 mm

500 mm

175Uxxxx

130BD884.10

Installation

VLT® Brake Resistor MCE 101

Orientation, compact and at-pack brake resistors

3.1.2 Steel Grid Brake Resistors

The steel grid brake resistors are designed for horizontal mounting only.

NOTICE

All resistors are cooled by natural convection. To ensure sucient airow and cooling, follow minimum clearances in Illustration 3.10 and Table 3.3.

Illustration 3.10 Minimum Clearances of all Steel Grid Brake

Resistors - Top View

Illustration 3.9 Orientation of Compact and Flat-pack Brake

Resistors

Derating with 20% is required when mounting the compact brake resistors horizontally. The enclosure protection of the IP21 types is reduced to IP20 when mounted horizontally.

Illustration 3.11 Minimum Clearances of all Steel Grid Brake

Resistors - Side View

175Uxxxx

130BD709.11

130BD595.10

Installation Design Guide

3 3

Illustration 3.12 Orientation of Steel Grid Brake Resistors

3.1.3 Accessories

Footprint brackets

The footprint bracket is an accessory used for mounting at-pack brake resistors.

Use the footprint bracket to mount the brake resistor at the rear of the frequency converter. Once mounted, the combined brake resistor and frequency converter occupy the same space in the cabinet as the frequency converter alone.

1 Frequency converter

2 Footprint mounting bracket

3 Flat-pack brake resistor

Illustration 3.13 Flat-pack Brake Resistor Mounted at Rear of

Frequency Converter

Part number Compatible brake resistor Compatible frequency

converter enclosure

size

175U0085

175U0087

175U0086

175U0088

Table 3.1 Selection Table

1x100 W at-pack

1x200 W at-pack

2x100 W at-pack

2x200 W at-pack

2x100 W at-pack

2x200 W at-pack

1x100 W at-pack

1x200 W at-pack

For mechanical dimensions for footprint brackets, see chapter 9.8.2 Mounting Brackets: Footprint.

130BD838.10

Fieldbus cable

Min. 200 mm

90° crossing

Brake resistor

130BD507.11

Installation

VLT® Brake Resistor MCE 101

L prole brackets

Electrical Installation

3.2

The L prole bracket is an accessory used for mounting at-pack brake resistors. The L prole brackets support

3.2.1 EMC Precautions

both horizontally and vertically mounting on a xed surface optimizing the required footprint.

The following EMC precautions are recommended to achieve interference-free operation of

eldbus cable(s) and

digital and analog inputs and outputs.

Observe relevant national and local regulations, for example regarding protective earth connection. Keep the eldbus cable(s) away from motor cables and brake resistor cables to avoid coupling of high frequency noise from one cable to another. Normally, a distance of 200 mm (8 inches) is sucient, but keeping the greatest possible distance between the cables is recommended, especially where cables run in parallel over long distances. When crossing is unavoidable, the eldbus cable(s) must cross motor cables and brake resistor cables at an angle of 90°, see Illustration 3.15.

Illustration 3.14 L Prole Bracket

Part number Compatible brake resistor

175U0009 1x200 W at-pack

175U0011

Table 3.2

1) Order 2x175U0011 for 300 W at-pack brake resistors.

For mechanical dimensions for L

1x100 W at-pack

1x300 W at-pack

prole brackets, see

chapter 9.8.1 Mounting Brackets: L Prole.

Illustration 3.15 Cable Routing

130BB154.12

130BF240.10

(1)

(2)

Installation Design Guide

3.2.2 Cable Connection

NOTICE

To comply with EMC emission specications, shielded/ armored cables are recommended.

NOTICE

Cables general: All cabling must comply with national and local regulations on cable cross-sections and ambient temperature.

3 3

See Table 3.3 for recommended temperature ratings for all cables and conductors connected to the brake resistor as ground connection, thermal switch, and brake power.

IP class Recommended cables

IP20

IP21

IP54

IP65

Table 3.3 Cable Temperature Ratings

1) For ground connection.

How to connect more than 1 resistor

Star parallel connection to ensure that load is shared evenly between 2 or more resistors.

≥80 °C (176 °F)

≥90 °C (194 °F)

(1) Twisted pair

(2) Shielded cable

Illustration 3.17 Twisted Cables

3.2.3 Brake Cable

Maximum length: 20 m (66 ft) shielded cable.

Ensure the connection cable to the brake resistor is shielded. Connect the shielding to the conductive back plate of the frequency converter and to the brake resistor metal cabinet, using cable clamps.

Protective Functions

3.3

3.3.1 Overtemperature Protection

Danfoss VLT® Brake Resistors MCE 101 is equipped with a galvanic isolated temperature switch (PELV) that is closed under normal operating conditions and open if the brake resistor is overheated.

NOTICE

Use the temperature switch as overtemperature protection feature to prevent damage of the brake resistor caused by overtemperature. To prevent damage to the brake resistor, perform an immediate stop or a ramp down.

There are several ways the temperature switch can be

Illustration 3.16 Connection of Several Brake Resistors

Brake resistors with xed cables

To reduce the electrical noise from the wires between the brake resistor and the frequency converter, twist the wires. For enhanced EMC performance, a metal shield can be used.

used:

The temperature switch as digital input to frequency converter Example 1

1. Connect terminal T1 of the brake resistor to the frequency converter terminal 12 or 13.

2. Connect terminal T2 of the brake resistor to a digital input, for example terminal 18.

Automatic restart after enabling of the temperature switch:

Select coast inverse for the selected digital input.

91 92 93 95

96 97 98 99

L1 L2 L3 PE

U V W PE

VLT

MCE 101

Brake resistor

RB1

RB2

L1 L2 L3 PE

R-

R+

+24V

D-in

130BD553.11

91 92 93 95

96 97 98 99

L1 L2 L3 PE

VLT

MCE 101

Brake resistor

T1 T2

RB1

RB2

R -

82R+

L1 L2 L3

S1 K1

U V W PE

130BD554.11

Installation

VLT® Brake Resistor MCE 101

Prevent automatic restart:

Example 2

Select latched start for the selected digital input.

NOTICE

Coast does not terminate the brake function.

Example 1

Illustration 3.19 Temperature Switch in both Motor and Brake

Resistor Disabling Mains Supply by an Input Contactor

Illustration 3.18 Temperature Switch in Brake Resistor

NOTICE

The temperature switch as input to the frequency converter cannot be considered a primary safety function. In case of a malfunction in the brake IGBT, the frequency converter and brake resistor are only protected by disconnecting the mains supply to the frequency converter. The temperature switch must be connected disabling the mains supply to the frequency converter by a contactor preventing dangerous overtemperatures.

The temperature switch disabling the mains supply to VLT by a contactor Example 2

1. Connect the brake resistor built-in thermal switch as controlling an input contactor. In this example, the thermal switch within the brake resistor is connected in series with the thermal switch within the motor.

2. Connect start and stop push buttons in series with the thermal switches.

3. Connect to a contactor in the mains supply in front of the frequency converter.

Thermal overheating in brake resistor or motor disables the mains supply to the frequency converter.

Thermo relay disabling the brake resistor Example 3

Calculate the brake current (I

thermo relay

) setting of the

temperature switch as follows:

thermo relay

brake resistor max

Rbr is the current brake resistor value calculated in chapter 4.1.2 Calculation of Brake Resistor Resistance.

Look up the brake current setting of the thermo relay for Danfoss brake resistors in chapter 8 Selection Guide.

Installation Design Guide

3.3.2 Brake Resistor and Brake IGBT

Brake resistor power monitor

In addition, the brake power monitor function makes it possible to read out the momentary power and the mean power for a selected time period. The brake can also monitor the power energizing and make sure that it does not exceed a limit selected in parameter 2-12 Brake Power Limit (kW). In parameter 2-13 Brake Power Monitoring, select the function to carry out when the power transmitted to the brake resistor exceeds the limit set in parameter 2-12 Brake Power Limit (kW).

NOTICE

Monitoring the brake power does not fulll a safety function. The brake resistor circuit is not ground leakage protected.

The brake is protected against short-circuiting of the brake resistor, and the brake transistor is monitored to ensure that short-circuiting of the transistor is detected. Use a relay or digital output to protect the brake resistor against overloading in the event of a fault in the frequency converter, see chapter 3.3.1 Overtemperature Protection.

3 3

Overvoltage control (OVC) can be selected as an alternative brake function in parameter 2-17 Over-voltage Control. If the DC-link voltage increases, this function is active for all units. The function ensures that a trip can be avoided. This is done by increasing the output frequency to limit the voltage from the DC link. It is a useful function, for example if the ramp-down time is too short since tripping of the frequency converter is avoided. In this situation, the ramp-down time is extended.

peak,mec.

175ZA096.14

VLT

termo

peak

avg

b, max

motor

INV

= 0.98

motor

= 0.9

System Integration

4 System Integration

VLT® Brake Resistor MCE 101

4.1 Brake Resistor Calculation

4.1.2 Calculation of Brake Resistor Resistance

To ensure the optimal selection of brake resistor for a given application, its inertia and braking prole calculations are required.

This chapter explains the calculations required to obtain values for optimal selection of brake resistor for a given application.

4.1.1 Brake Set-up

The following sections use expressions and abbreviations related to the brake set-up in Illustration 4.1.

To prevent the frequency converter from cutting out for protection when the motor brakes, select resistor values on the basis of the peak braking power and the DC-link voltage:

Rbr =

peak

Udc

The brake resistor performance depends on the DC-link voltage (Udc).

Udc is the voltage, where the brake is activated. The FCseries brake function is settled depending on the mains supply.

DC-link voltage (Udc), VLT® AutomationDrive FC 360

Size [V]

FC 360 3x380–480,

0.37–22 kW (0.5–30

hp)

FC 360 3x380–480,

30–75 kW (40–100

hp)

Brake

active

[V DC]

700–770

N/A

Overvoltage

warning

[V DC]

800 800

Overvoltage

alarm

[V DC]

Illustration 4.1 Brake Set-up

Table 4.1 DC-link Voltage (Udc), FC 360

1) Adjustable with parameter 2-14 Brake voltage reduce

2) No built-in brake option

Use the brake resistance R

, to ensure that the frequency

rec

converter is able to brake at the highest braking torque (M

) (for example 160%). The formula is written as:

br(%)

Ω =

η η

rec

motor

VLT

motor

is typically at 0.90

is typically at 0.98

x M

br ( % )

x 100

x η

VLT

x η

motor

When a higher brake resistor resistance is selected, 160%/ 150%/110% braking torque cannot be obtained, and there is a risk that the frequency converter cuts out of DC-link overvoltage for protection.

For braking at lower torque, for example 80% torque, it is possible to install a brake resistor with lower power rating. Calculate size using the formula for calculating R

rec

P [W]

peak

avg

t [s]

175ZA094.13

System Integration Design Guide

4.1.3 Calculation of Braking Power

When calculating the braking power, ensure that the brake resistor is scaled for the average power as well as the peak power.

The average power is determined by the process

•

period time, that is the length of the braking time in relation to the process period time.

The peak power is determined by the braking

•

torque, which means that as braking progresses, the brake resistor must be able to dissipate the energy input.

Illustration 4.2 shows the relation between the average power and the peak power.

4.1.5 Calculation of the Brake Resistor Average Power

The average power is determined by the length of the braking time in relation to the process period time.

When the kinetic energy (Eb) transferred to the resistor in each braking sequence is known (see chapter 6.1 Conveyor Belt and chapter 6.2 Centrifuge), calculate the average power of the brake resistor as follows:

Tb × 100

avg

Tp = period time in s, see Illustration 4.2.

When the kinetic energy transferred to the resistor in each braking sequence is not known, calculate the average power based on the process period time and the braking time.

Calculate the duty cycle for the braking sequence as follows:

Duty cycle =

where

4 4

Illustration 4.2 Relation between Average Power and Peak

Power

Process period time in s

Braking time in s

4.1.4 Calculation of the Brake Resistor Peak Power

P the motor shaft. Calculate P

P when the motor brakes.

P the eciencies of the motor and the frequency converter.

Calculate P

When the brake resistor recommended by Danfoss is selected (R chapter 8 Selection Guide, the brake resistor is certain to provide a braking torque of 160%/150%/110% on the motor shaft.

is the peak power by which the motor brakes on

peak, mec

as follows:

peak, mec

= P

peak, mec

is the braking power dissipated to the brake resistor

peak

is lower than P

peak

= P

peak

motor

× M

motor

as follows:

peak

× M

) on the basis of the tables in

rec

BR( %)

since the power is reduced by

peak,mec

× η

BR( %)

motor

VLT

Tp = process period time in s

Tb = braking time in s

Danfoss oers brake resistors with a duty cycle of maximum 10% and 40%. If a 10% duty cycle is applied, the brake resistors are able to absorb P

for 10% of the

peak

period time. The remaining 90% of the period time is used on deecting excess heat.

Calculate the average power with 10% duty cycle as follows:

avg

= P

× 10 %

peak

Calculate the average power with 40% duty cycle as follows:

avg

= P

× 40 %

peak

The calculations apply to intermittent braking using a period time of 30 s.

NOTICE

Exceeding the specied intermittent braking period time may result in overheating the resistor.

ω Start

ω Stop

∆t

∆ω/∆t

175ZA863.11

System Integration

VLT® Brake Resistor MCE 101

4.1.6 Braking of Inertia

When braking high inertia values on the motor shaft, base the brake resistor values on the inertia, Δω, Δt, see Illustration 4.3.

Illustration 4.3 Braking of High Inertia

Δt is determined by the ramp-down time.

NOTICE

The ramp-down time goes from the rated motor frequency to 0 Hz.

can be calculated as:

peak

2 × π

Δω

Δt

Δn

Δt

peak

= η

motor

× η

VLT

× n

× ω

start

j is the motor shaft inertia.

× j ×

Parameters Design Guide

5 Parameters

For descriptions of all available parameters, see VLT

AutomationDrive FC 360 Programming Guide, which is available from drives.danfoss.com/knowledge-center/ technical-documentation/.

2-10 Brake Function

Option: Function:

[0]*O No brake resistor is installed.

[1] Resistor

brake

[2] AC brake Improve braking without using a brake resistor.

A brake resistor is incorporated in the system for

dissipating surplus brake energy as heat.

Connecting a brake resistor allows a higher DC-

link voltage during braking (generating

operation). The brake resistor function is only

active in frequency converters with an integral

dynamic brake.

This parameter controls an overmagnetization of

the motor when running with a generatoric load.

This function can improve the OVC function.

Increasing the electrical losses in the motor

allows the OVC function to increase braking

torque without exceeding the voltage limit.

NOTICE

The AC brake is not as ecient as dynamic braking with resistor. AC brake is for VVC+ mode in both open and closed loop.

2-12 Brake Power Limit (kW)

Range: Function:

Size

related*

[0.001 -

2000

kW]

Parameter 2-12 Brake Power Limit (kW) is the

expected average power dissipated in the

brake resistor over a period of 120 s. It is

used as the monitoring limit for

parameter 16-33 Brake Energy Average and

species when a warning/alarm is given.

To calculate parameter 2-12 Brake Power

Limit (kW), the following formula can be

used.

br, avg

is the average power dissipated in

br,avg

the brake resistor. Rbr is the resistance of

the brake resistor. tbr is the active breaking

time within the 120 s period Tbr.

Ubr is the DC voltage where the brake

resistor is active. For T4 units, the DC

voltage is 778 V, which can be reduced by

parameter 2-14 Brake voltage reduce.

NOTICE

If Rbr is not known or if Tbr is dierent from 120 s, the practical approach is to run the brake application, read out parameter 16-33 Brake Energy Average, and then enter this value + 20% in

parameter 2-12 Brake Power Limit (kW).

W =

V × tbrs

RbrΩ × Tbrs

5 5

2-11 Brake Resistor (ohm)

Range: Function:

Size

related*

[ 0 -

65535

Ohm]

Set the brake resistor value in Ω. This

value is used for monitoring the power to

the brake resistor. Parameter 2-11 Brake

Resistor (ohm) is only active in frequency

converters with an integral dynamic brake.

Use this parameter for values without

decimals.

2-14 Brake voltage reduce

Range: Function:

0 V* [ 0 - 0 V] Setting this parameter may change the brake

resistor (parameter 2-11 Brake Resistor (ohm)).

2-16 AC Brake, Max current

Range: Function:

100 %* [0 -

160 %]

Enter the maximum allowed current when

using AC brake to avoid overheating of

motor windings.

NOTICE

Parameter 2-16 AC Brake, Max current

has no eect when parameter 1-10 Motor Construction is set to [1] PM, non-salient SPM.

Parameters

2-17 Over-voltage Control

Option: Function:

Overvoltage control (OVC) reduces the risk of

the frequency converter tripping due to an

overvoltage on the DC link caused by

generative power from the load.

[0] * Disabled No OVC required.

[1] Enabled

(not at

stop)

[2] Enabled Activate OVC.

Activate OVC except when using a stop signal

to stop the frequency converter.

VLT® Brake Resistor MCE 101

CAUTION

PERSONAL INJURY AND EQUIPMENT DAMAGE

Enabling OVC in hoisting applications may lead to personal injuries and equipment damage.

DO NOT enable OVC in hoisting

•

applications.

Application Examples Design Guide

6 Application Examples

6.1 Conveyor Belt

Illustration 6.1 shows the relation between the braking power and the acceleration/braking of a conveyor belt. Note:

The motor power during braking is negative,

•

since the torque on the motor shaft is negative.

The motor power is time-dependent.

•

The braking power (the power to be dissipated to the brake resistor) corresponds almost exactly to the negative motor power plus losses in the motor and the frequency converter.

Kinetic energy (E) in conveyor belt + motor:

E = 0 . 5 × m × v2 + 0 . 5 × j × ω2Ws

where

m = mass with linear movement [kg].

v = speed of mass with linear movement [m/s].

j = inertia of motor and gear box [kgm2].

ω = motor speed [rad/s].

ω = motor speed =

n × 2π

rad/ s

This formula is also expressed as follows:

E = 0 . 50 × m × v2 + 0 . 0055 × j × n2Ws

However, not all of the energy is dissipated in the brake resistor. The friction of the conveyor belt and the power loss of the motor also contribute to the braking function. So, the formula for energy dissipation (Eb) to the brake resistor is as follows:

= 0 . 5 × m v

where

Mf = Friction torque [Nm].

ŋM = Motor

Insert:

n × 2π

ω =

The result is:

= 0 . 5 × m v

+ 0 . 5 jω

+ 0 . 0055 × j × n

− 0 . 5 × M

eciency.

ω × η

− 0 . 052 × n × Mf × ηM Ws

average

Time [s]

Length [m]

175ZA397.14

Acceleration

Braking

braking, avg.

[W]

Motor power

[W]

Brake power

[Nm]

Torque

[m/s]

Speed

VLT®

[m/s]

Speed

m v

[m/s]

Application Examples

VLT® Brake Resistor MCE 101

Illustration 6.1 Conveyor Belt: Relation Between Braking Power and Acceleration/Deceleration

Application Examples Design Guide

6.2 Centrifuge

Illustration 6.2 Centrifuge with Brake Resistor

Illustration 6.2 shows braking of a centrifuge, which is a typical application of brake resistors. The formula for energy dissipation (Eb) to the brake resistor is:

Eb = 0 . 0055 × jc × n22 + 0 . 0055 × jM × n12 × ηM Ws

where

m = weight of the centrifuge content [kg].

jC = centrifuge inertia [kgm2] = 0.5 x m (r

jM = gear motor inertia [kgm2].

ηM = gear motor

n1 = maximum motor speed [RPM].

n2 = maximum centrifuge speed [RPM].

Rb = brake resistor.

Continuous Braking

6.3

To achieve continuous braking, select a brake resistor in which the constant braking power does not exceed the average power P

avg

eciency.

of the brake resistor.

+ r

NOTICE

Contact the Danfoss distributor for further information.

175ZA093.10

Special Conditions

7 Special Conditions

VLT® Brake Resistor MCE 101

7.1 Alternative Braking Methods

7.1.1 DC Injection Braking

If the 3-phase winding of the stator is fed with direct current, a stationary magnetic stator bore causing a voltage to be induced in the bars of the cage rotor as long as the rotor is in motion. Since the electrical resistance of the rotor cage is very low, even small induced voltages can create a high rotor current. This current produces a strong braking eect on the bars and hence on the rotor. As the speed decreases, the frequency of the induced voltage decreases and with it the inductive impedance. The ohmic resistance of the rotor gradually

becomes dominant and so increases the braking eect as the speed decreases. The braking torque generated decreases steeply just before standstill and nally ceases when there is no further movement. Direct current injection braking is therefore not suitable for holding a load at rest.

eld Φ is set up in the

7.1.4 DC Braking

Resistor brake is useful from maximum speed down to a certain frequency. Below this frequency, DC braking is to be applied as required. The most ecient way of doing this is to use a combination of dynamic braking and DC braking. See Illustration 7.1. The parameters are in chapter 5 Parameters.

7.1.2 AC-braking

When the motor acts as a brake, the DC-link voltage increases because energy is fed back to the DC-link. The principle in AC brake is to increase the magnetization during the braking and thereby increase the thermal losses of the motor.

Illustration 7.1 Optimum Braking

How to calculate optimum DC-brake cut in frequency:

7.1.3 Mechanical Holding Brake

n0 − n

A mechanical holding brake mounted directly on the motor shaft normally performs static braking. In some applications, the static holding torque is working as static holding of the motor shaft (usually synchronous permanent motors). A holding brake is either controlled by a PLC or directly by a digital output from the frequency converter (relay or solid state).

Slip s =

Synchronous speed n0 =

f = frequency supplied to motor. p = number of pole pairs. nn = speed of the rotor.

× 100

f × 60

[1/min]

NOTICE

When the holding brake is included in a safety chain: A frequency converter cannot provide a safe control of a mechanical brake. A redundancy circuitry for the brake control must be included in the total installation.

DC-brake cut in frequency = 2 ×

s × f

100

Select a 10% duty cycle brake resistor from the

selection tables

Select a 10% duty cycle brake resistor from the selection tables

Select a 40% duty cycle brake resistor from the

selection tables

Please contact

Danfoss

Please contact

Danfoss

130BB148.13

Low intertia

ramp down>15 s

Low or high

intertia?

Horizontal

Vertical

Horizontal or

vertical movement?

Determine braking

time of the application

Braking time<

brake resistor period

Braking time>

brake resistor period

Calculate duty

cycle

duty cycle <10% duty cycle >40%

duty cycle ranging

from 10-40%

High inertia

ramp down<15 s

or don’t know

Compare the braking

time with the resistors

braking period

Selection Guide Design Guide

8 Selection Guide

8.1 Selection Flow Chart

To select the correct size of brake resistor for an application, refer to the ow chart in Illustration 8.1.

1. Select an answer to each question from the top down.

2. Follow the answer to reach the next question, or to obtain guidance in calculating inertia or duty cycle.

3. The nal box indicates the correct selection table, or whether to call hotline for additional guidance.

Illustration 8.1 Brake Resistor Selection Flow Chart

1) When contacting Danfoss, provide the following data: Nominal power 100%

•

Maximum power during brake cycle

•

Braking time/duty cycle

•

Supply voltage (maximum DC)

•

Resistance (Ω)

•

With or without temperature switch

•

IP enclosure rating

•

Type of reference drive

•

8 8

Selection Guide

VLT® Brake Resistor MCE 101

8.2 Selection Tables for Recommended Brake Resistors

8.2.1 Abbreviations used in the Brake Resistor Tables

Mains Voltage class.

min

rec

Thermo relay Brake current setting of external thermo relay.

Danfoss part number Danfoss brake resistor order numbers.

Cable cross-section

br,cont.

br,nom

8.2.2

VLT® AutomationDrive FC 360

10% duty cycle, horizontal braking, T4

Frequency converter data

Mains

type

[kW

(hp)]

T4 0.75 (1) 434 509 630 0.1 (0.13) 175u3002 – – – 1.5 (16) 0.4

T4 1.1 (1.5) 288 338 410 0.1 (0.13) 175u3004 – – – 1.5 (16) 0.5

T4 1.5 (2) 208 244 270 0.2 (0.27) 175u3007 – – – 1.5 (16) 0.8

T4 2.2 (3) 139 164 200 0.2 (0.27) 175u3008 – – – 1.5 (16) 0.9

T4 3 (4) 100 119 145 0.3 (0.4) 175u3300 – – – 1.5 (16) 1.3

T4 4 (5.5) 74.0 87.9 110 0.45 (0.6) 175u3335 175u3450 175u3449 – 1.5 (16) 1.9

T4 5.5 (7.5) 54.0 63.3 80 0.57 (0.76) 175u3336 175u3452 175u3451 – 1.5 (16) 2.5

T4 7.5 (10) 38.0 46.1 56 0.68 (0.91) 175u3337 175u3027 175u3028 – 1.5 (16) 3.3

T4 11 (15) 27.0 33.0 38 1.13 (1.5) 175u3338 175u3034 175u3035 – 1.5 (16) 5.2

T4 15 (20) 19.0 24.0 28 1.4 (1.9) 175u3339 175u3039 175u3040 – 1.5 (16) 6.7

T4 18.5 (25) 16.0 19.4 22 1.7 (2.28) 175u3340 175u3047 175u3048 – 1.5 (16) 8.3

T4 22 (30) 16.0 18.0 19 2.2 (3) 175u3357 175u3049 175u3050 – 1.5 (16) 10.1

T4 30 (40) 11.0 13.8 14 2.8 (3.8) 175u3341 175u3055 175u3056 – 2.5 (14) 13.3

T4 37 (50) 9.0 11.1 12 3.2 (4.3) 175u3359 175u3061 175u3062 – 2.5 (14) 15.3

T4 45 (60) 8.0 9.1 9.5 4.2 (5.6) – 175u3065 175u3066 – 4 (12) 20

T4 55 (75) 6.0 7.4 7.0 5.5 (7.4) – 175u3070 175u3071 – 6 (10) 26

T4 75 (100) 4.0 5.4 5.5 7 (9.4) – – – 175u3231 10 (8) 36

0.37

(0.5)

0.55

(0.75)

Rated motor size for frequency converter.

Minimum allowed brake resistor - by frequency converter.

Recommended brake resistor resistance of Danfoss brake resistors.

Recommended minimum value based upon PVC insulated copper cable. 30 °C (86 °F) ambient temperature with

normal heat dissipation.

Brake resistor average rated power. The temperature switch enables at approximately 90% of continuous rated

power at brake resistors with IP54, IP21, and IP65 enclosure protection.

The nominal (calculated) resistor value to ensure a brake power on motor shaft of 150/160/110% for 1 minute.

FC 360 Horizontal braking 10% duty cycle

Brake resistor data Installation

Danfoss part number Cable

Screw

[Ω]

min

890 1042 1200 0.1 (0.13) 175u3000 – – – 1.5 (16) 0.3

593 694 850 0.1 (0.13) 175u3001 – – – 1.5 (16) 0.4

br,nom

[Ω]

rec

br,cont.

[kW (hp)]

Wire IP54

terminal

IP21

Screw

terminal

IP65

Bolt

connection

IP20

cross-

section

[mm

(AWG)]

Thermo

relay

[A]

Table 8.1 T4, Horizontal Braking 10% Duty Cycle

Selection Guide Design Guide

40% duty cycle, vertical braking, T4

FC 360 Vertical braking 40% duty cycle

Frequency converter data

Mains

type

[kW

(hp)]

0.37

(0.5)

0.55

(0.75)

[Ω]

min

[Ω]

br,nom

[Ω]

rec

br,cont.

[kW (hp)]

890 1042 1200 0.2 (0.27) 175u3101 – – – 1.5 (16) 0.4

593 694 850 0.2 (0.27) 175u3308 – – – 1.5 (16) 0.5

T4 0.75 (1) 434 509 630 0.2 (0.27) 175u3309 – – – 1.5 (16) 0.7

T4 1.1 (1.5) 288 338 410 0.45 (0.6) 175u3310 175u3416 175u3415 – 1.5 (16) 1

T4 1.5 (2) 208 244 270 0.57 (0.76) 175u3311 175u3418 175u3417 – 1.5 (16) 1.4

T4 2.2 (3) 139 164 200 0.96 (1.29) 175u3312 175u3420 175u3419 – 1.5 (16) 2.1

T4 3 (4) 100 119 145 1.13 (1.5) 175u3313 175u3422 175u3421 – 1.5 (16) 2.7

T4 4 (5.5) 74.0 87.9 110 1.7 (2.3) 175u3314 175u3424 175u3423 – 1.5 (16) 3.7

T4 5.5 (7.5) 54.0 63.3 80 2.2 (3) 175u3315 175u3138 175u3139 – 1.5 (16) 5

T4 7.5 (10) 38.0 46.1 56 3.2 (4.3) 175u3316 175u3428 175u3427 – 1.5 (16) 7.1

T4 11 (15) 27.0 33.0 38 5 (6.7) – – – 175u3236 1.5 (16) 11.5

T4 15 (20) 19.0 24.0 28 6 (8) – – – 175u3237 2.5 (14) 14.7

T4 18.5 (25) 16.0 19.4 22 8 (10.7) – – – 175u3238 4 (12) 19

T4 22 (30) 16.0 18.0 19 10 (13.4) – – – 175u3203 4 (12) 23

T4 30 (40) 11.0 13.8 14 14 (19) – – – 175u3206 10 (8) 32

T4 37 (50) 9.0 11.1 12 17 (23) – – – 175u3210 10 (8) 38

T4 45 (60) 8.0 9.1 9.5 21 (28) – – – 175u3213 16 (6) 47

T4 55 (75) 6.0 7.4 7.0 26 (35) – – – 175u3216 25 (4) 61

T4 75 (100) 4.0 5.4 5.5 36 (48) – – – 175u3219 35 (2) 81

Brake resistor data Installation

Danfoss part number Cable

cross-

section

[mm

(AWG)]

Wire IP54

Screw

terminal

IP21

Screw

terminal

IP65

Bolt

connection

IP20

Thermo

relay

[A]

8 8

Table 8.2 T4, Vertical Braking 40% Duty Cycle

Specications

VLT® Brake Resistor MCE 101

9 Specications

9.1 Ambient Conditions

Environment Ambient temperature range -40 to 70 °C (-40 to 158 °F) Temperature range during storage/transport -40 to 70 °C (-40 to 158 °F) Maximum temperature at housing 300 °C (572 °F) Maximum relative humidity 5–85%, non-condensation during operation Power derating as a function of ambient temperature. (100% power rating and pulse-load):

- Steel grid brake resistors, IP20 Continuous power 100% @ 40 °C (104 °F) to 70% @ 70 °C (158 °F), linear

- Aluminum-housed compact brake resistors,

IP21 Continuous power 100% @ 40 °C (104 °F) to 75% @ 70 °C (158 °F), linear

- Aluminum-housed brake resistors - compact

and at-pack, IP54 Continuous power 100% @ 40 °C (104 °F) to 75% @ 70 °C (158 °F), linear

- Aluminum compact brake resistors, IP65 Continuous power 100% @ 40 °C (104 °F) to 50% @ 70 °C (158 °F), linear

Power derating at vertical mounted resistor (wall-mounted) when mounted horizontal (100% power rating and pulseload):

- Aluminum-housed at-pack brake resistors, IP54 No derating

- Aluminum-housed compact brake resistors, IP21, IP54, IP65 -20%

Cooling requirements: The brake resistors are cooled by free natural convection. The power ratings of the resistors refers to cooling conditions

with free natural cooling. The requirements for minimum clearances must be observed during installation. Derating at high altitudes 100% @ 1000 m (3281 ft) above sea level Derating at high altitudes 94% @ 1500 m (4921 ft) above sea level Derating at high altitudes 82% @ 3000 m (9843 ft) above sea level

9.2 General Electrical Specications

Electrical specications Resistance tolerances ±10% Insulation >20 MΩ @ 1000 V Dielectric strength 2500 V AC for 1 minute Operating voltage:

- Aluminum-housed compact brake resistors, IP54 UL: 600 V AC/600 V DC

- Aluminum-housed compact brake resistors, IP54 IEC: 690 V AC/1100 V DC

- Aluminum-housed at-pack brake resistors, IP54 UL: 1000 V AC/1400 V DC

- Aluminum-housed at-pack brake resistors, IP54 IEC: 1000 V AC/1400 V DC

- Aluminum-housed compact brake resistors, IP21, IP65 UL: 600 V AC/600 V DC

- Aluminum-housed compact brake resistors, IP21, IP65 IEC: 690 V AC/1100 V DC

- Steel grid brake resistors, IP20 IEC: 690 V AC/1100 V DC

Power rating (continuous load 100%) with and without temperature switch

- Without temperature switch 100% of continuous power rating @ 40 °C (104 °F)

- With temperature switch, steel grid brake resistors, IP20 100% of continuous power rating @ 40 °C (104 °F)

- With temperature switch, aluminum-housed brake resistors,

IP21, IP54, IP65 Minimum 80% of continuous power rating @ 40 °C (104 °F)

- With temperature switch, aluminum-housed brake

resistors, IP21, IP54, IP65 Electrical data temperature switch:

- Steel grid brake resistors, IP20 10 A, 250 V AC, normally closed (NC). Enables at 260 °C (500 °F)

- Aluminum-housed brake resistors, IP21, IP54, IP65 2 A, 250 V AC, normally closed (NC). Enables at 180 °C (356 °F)

Temperature switch enables at ≥80% of the continuous power rating

@ 40 °C (104 °F)

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