Danfoss MCB 112 Fact sheet

Fact Sheet

VLT® PTC Thermistor Card MCB 112

VLT® PTC Thermistor Card MCB 112 improves the motor condition surveillance in the Danfoss VLT® AutomationDrive, VLT® HVAC Drive and VLT® AQUA Drive frequency converters, compared to the standard built-in ETR function with thermistor terminal.

The MCB 112 option enables VLT® drives to be used in systems that require control of motors located in potentially explosive environments. When MCB 112 is used with a VLT® drive with integrated Safe Torque Off, the drive is certified to coast the motor when motor temperature becomes too high. This helps to eliminate the risk of explosion due to an over-temperature condition in the ATEX-certified motor (Ex d, Ex e, Ex n, Ex tb and Ex tc).

ATEX Directive 94/9/EC is an EU directive that describes equipment permitted in an environment with a potentially explosive atmosphere.

The option is ATEX certified for protection of certified Ex proof motors, regardless of supplier, in zones 1 and 2 (gas) and zones 21 and 22

(dust), in accordance with the dedicated additional measures of the Ex protection system of the motor.

The frequency converter itself is not ATEX rated and must be situated outside the hazardous area.

The Safe Torque Off function can be used with external safety devices (with integrated “&” function) and is compatible with simultaneous use of the MCB 112.

Collaboration and approval

The MCB 112 is a standard plug-in option for VLT® AutomationDrive, VLT® HVAC Drive and VLT® AQUA Drive with integrated Safe Torque Off.

Alarm handling

The MCB 112 surveillance function detects motor overheating, possible short circuits, or open circuit due to breaks in the sensor circuit. It also provides alarm logging, diagnosis and intelligent evaluation, thus facilitating troubleshooting.

Integrated Safe Torque Off

The MCB 112 uses the Safe Torque Off function of the drive which is approved in accordance with SIL2 EN 61508. A mains disconnect contactor is not necessary.

Feature Benefit

Independent of motor supplier Flexible choice of motor type No binding between the different components Easy service

Temperature surveillance is performed directly in the frequency converter

Can assume sole protection of an Ex d, Ex e, Ex n, Ex tb and Ex tc certified motor within the installation/facility

Current limiting feature (only VLT® AutomationDrive)

Integrated safety technology Reduced cabling and commissioning cost

Plug-and-play

Isolated solution (PELV)

The MCB 112 has been developed in collaboration with the company ZIEHL industrie-elektronik, an experienced specialist in thermal motor protection in potentially explosive atmospheres, approved by the PTB (PhysikalischTechnische Bundesanstalt).

Suitable for operation of Ex d, Ex e & Ex n and Ex tb & Ex tc certi ed motors

– No external components needed – Less space required – Reduced system cost

External components saved

Less costly Ex-e motors can be applied

– Swift and cost-efficient upgrade on-site – The drive automatically identifies the option

Digital outputs are galvanically isolated from supply and high-voltage

www.vlt-drives.danfoss.com

Thermistor relay

Contactor

Stop

Non-explosive hazard zone

ATEX certified motor

Explosive hazard zone

The integrated MCB 112 replaces external components like thermistor relay, contactor and wiring, since the drive communicates directly with the motor.

Current limiting feature

VLT® AutomationDrive has a feature that makes it possible to apply “Ex-e” certified motors instead of the more expensive “Ex-d” certified motors for ignition protection. The combination of the parameter setup and the MCB 112 ensures that the VLT® AutomationDrive will never provide sufficient current to cause the motor to overheat.

The feature is easy to use

Enter relevant data from the motor name plate via variable speed current limit parameters in the frequency converter. From this data, the drive creates an upper limit that limits the current provided dependent upon the motor speed.

Uncomplicated

Flexible use of speed control with motors certified with increased safety “e” ignition protection.

Compact

With increased safety “e” certification, distinctly smaller frame size, lower weight and lower costs compared to speed control of motors with flameproof enclosure “d” certification.

Flexible

Easy mix and match, resulting in smaller stocks of motors and frequency converters.

Specifications

PTC-thermistor connection

Monitoring function Temperature monitoring by means of PTC sensors PTC compliant with DIN 44081, DIN 44082 Number of sensors in series Set with 3 -...6 resistors

Cut-out-point 3.3 kΩ .... 3.65 kΩ ... 3.85 kΩ

Reclosing point 1.7 kΩ .... 1.8 kΩ ... 1.95 kΩ

Collective resistance cold sensors < 1.65 kΩ Terminal voltage (sensors) ≤ 2.5 V for R ≤ 3.65 kΩ, ≤ 9 V for R = ∞ Terminal current (sensors) ≤ 1 mA Short circuit 20 Ω ≤ R ≤ 40 Ω Max. sensor cable length for short-circuit detection 2 × 250 m with 0.5 mm

Testing conditions

EN 60 947-8 Rated impulse voltage 6000 V Over voltage category III Contamination level 2 EMC – Immunity industry standard EN61000-6-2 EMC – Emission industry standard EN61000-6-4

Safety-related parameters

EN 61508 for Ta = 40° C ongoing SIL 2 HFT Type A PFD (test interval one year) 3,37E-04 SFF 78% λ

2,35E-07 3,73E-08

7,69E-08 MTBF 179 years Operating mode Low demand mode Hardware architecture 1oo1

Ordering number: 130B1137

1.1

0.9

0.8

I/In

0.7

0.6

0.5

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105

Incorrect area

Correct area

Star connection

Delta connection

f/Hz

Variable speed current limitation, from the EC type-e xamination certiﬁ cate of the Ex e motor. Enter the relevant information from the motor nameplate into the control panel of the drive. Then the drive will calculate max. current in relation to the motor speed. The curve represents the limit under which the current must be kept to prevent overheating of the motor. The nodes for the curves are determined by measurement from the Ex notiﬁ ed body. With a second protective device like the MCB 112, direct temperature monitoring is possible via a triple PTC thermistor circuit. Direct temperature monitoring also detects malfunctions such as blocked ventilation or inadmissibly high ambient temperatures.

Economical

Lower investment costs enable faster payback when speed control is used to achieve energy savings.

No need for matched pairs

Suitable for operation of Ex d, Ex e, Ex n, Ex tb and Ex tc certified motors without the need for matched pair motor-drive.

Universal

Universal solution for the entire power range of 0.25 to 630 kW.

, 2 × 800 m with 1.5 mm

Danfoss VLT Drives, Ulsnaes 1, DK-6300 Graasten, Denmark, Tel. +45 74 88 22 22, Fax +45 74 65 25 80, www.danfoss.com/drives, E-mail: info@danfoss.com