schneider VW3 A7 201 User Manual

Altivar 71

Network braking units

User’s manual

VW3 A7 201 ... 241

11/2010

1757361

www.schneider-electric.com

Contents

Before you begin______________________________________________________________________________________________ 4 Steps for setting up the braking unit_______________________________________________________________________________ 5 Checking the installation__________________________________________________________ ______________________________ 6 Recommendations ___________________________________________________________________________________________ 13 Characteristics ______________________________________________________________________________________________ 14 Sizing _____________________________________________________________________________________________________ 15 Dimensions________________________________________________________________________________ _________________ 19 Mounting and temperature conditions ____________________________________________________________________________ 21 Recommendations for the electrical installation_____________________________________________________________________ 22 Connection diagrams, fuses and associated cables__________________________________________________________________ 23 Operation on a neutral IT (isolated or impedance grounded neutral) system_______________________________________________ 28 Electromagnetic compatibility and wiring __________________________________________________________________________ 29 Starting tests________________________________________________________________________________________________ 33 Configuration _______________________________________________________________________________________________ 34 Troubleshooting _____________________________________________________________________________________________ 36

1757361 11/2010 3

Before you begin

Read and understand these instructions before performing any procedure with this braking unit.

DANGER

HAZARDOUS VOLTAGE

• Read and understand this User’s Manual before installing or operating the braking unit. Installation, adjustment, repair, an d maintenance must be performed by qualifi ed personnel.

• The user is responsible for compliance with all international and national electrical standards in force concerning protective grounding of all equipment.

• Many parts in this equipment, including printe d circuit boards, o perate at line voltage . DO NOT TOUCH. Use only electrically insulated tools.

• DO NOT touch unshielded components or terminal strip screw connections with voltage present.

• DO NOT short across terminals PA and PC or across the DC bus capacitors.

• Install and close all the covers before applying power or starting and stopping the drive.

• Before servicing the braking unit

- Disconnect the power and the control power supply.

- Place a “DO NOT TURN ON” label on the disconnect at the head of the installation.

- Lock the disconnect in the open position.

• Disconnect the power supply, including the 230 V control power supply, before working on the equipment. Wait for the charging LED to go of f. Then follow the DC bus voltage measurement procedure described in the drive Installation Manual to verify that the DC voltage is less than 45 VDC. The LEDs on the speed drive are not accurate indicators of the absence of DC bus voltage.

Electric shock will result in death or serious injury.

4 1757361 11/2010

Steps for setting up the braking unit

Steps 1 to 4 must be performed with the power off

b 1 Take delivery of the braking unit (see page 13)

v Check that the catalog number printed on the label is the same

as that on the purchase order.

v Remove the braking unit from its packaging and check that it has

not been damaged in transit.

b 2 Check the line voltage (see page 14)

v Check that the line voltage is compatible with the voltage

range of the braking unit

b 3 Install the braking unit (see page 21)

v Mount the braking unit in accordance with the

instructions in this document

v Install any internal and external options

b 4 Wire the braking unit (see page 23)

v Connect the braking unit to the 3-phase supply

(L1,L2,L3)

v Connect the braking unit to the drive DC bus v

Connect the control cable

1757361 11/2010 5

Checking the installation

max

CUΔ

()

⋅

------------------------------ -

max

Δ⋅

L'⋅

------------------------- -

ZKD

-------------

–=

Length of the DC bus

The maximum inductance of the DC bus connecting output PA/+, PC/- on the drive to the braking unit must not exceed a set level, as this inductance results in an additional difference i n potential on the DC bus when the IGBTs are open. To avoid an overload on the components of the braking unit, this difference in potential must not exceed 10 0 VDC. The maximu m inductan ce can be calcu lat ed us ing thi s and other characteristics of the braking unit (value of the DC bus capacitors and absolute value of the grid current).

This inductance must always be greater than or equal to the sum of the inductance of the DC bus on the frequency inverter and the inductance of the DC bus connection cables. The inductance of the DC bus on the frequency inverter must always be taken into consideration. The inductance per unit of length of the cables generally used for the power supply is in the region of 0.6 µH/m. The maximum length of the conductors l

max is calculated according to the following information:

• Values of the input capacities C

• Maximum DC voltage edge permitted during motor generator operation (ΔU

• Maximum AC current level for the equipment î (=2*Irms)

• Inductance per unit of length L'

• Inductance of the coil Lzkd of the DC bus The equation below can be used to calculate l

max:

GL=100 VDC)

Typical capacity of the DC connection inside the braking unit

Braking unit Power

VW3 A7 ...

Example: C = 200 μF,

For longer DC bus cables, additional capacitors must be installed (Please contact your local representative)

ΔU

= 100 V, i = 271 A, a = 80 mm, r = 8.5 mm, μ0=1.257.10-6H/m

7 - 45 kW 100 μF 70 - 135 kW 200 μF 160 - 200 kW 420 μF

capacity

6 1757361 11/2010

Checking the installation

VW3A7...

0.4kV

100kVA 20kW

20kW

ATV71

Operation on a generator

It is possible to use a braking unit with an isolated line supply (for example: a diesel engine generating set), but there are restrictive rules limiting the power.

With a line supply whose architecture is similar to that shown in the diagram above, there are 2 additional restrictions:

• The power of the motor connected to the inverter must be less than half the nominal power of the generator.

• The total power of the two other loads must be more than double the power returned on the line supply. If these conditions are not verified, changing the motor to operation as a generator could result in a sudden overload. This overload is too

high for the voltage regulator of the generator. The regulator reacts with an overshoot which leads to an overvoltage with the isolated line supply.

CAUTION

RISKS OF INTERFERENCE

Overvoltages can cause serious damage to the frequency inverter and/or the braking unit and the other loads.

Failure to follow this precaution can result in equipment damage.

1757361 11/2010 7

Checking the installation

R Tr

10kV

0.4kV

100kVA 60kW

20kW

ATV71

VW3A7...

Operation on a transformer

If only some loads are operating on one section of the line supply, then the transformer that is connected must be capable of transporting the unused generated power from this section to the next voltage level without exceeding the voltage edge permitted in the line supply section. The nominal power of the transformer must therefore be one and a half times gr eater than the power generated outside the se ction, so that the harmonic and reactive components of the current can be transmitted. In the line supply section shown in the diagram below, these conditions are verified even if the other loads are disconnecte d.

If the power that is generated is in the region of the nominal power of the transformer, then the transformer short circuit voltage must be fairly low (6% maximum) to limit the voltage increase in this section.

The operation of the braking unit used with a sized transformer (for example in the case of a slip ring induction motor) is only permitted if the ratio of the power generated to the nominal power is considerably less than 1.

8 1757361 11/2010

Checking the installation

ATV71

Prohibited

Position of the commutation reactor

If the frequency inverter is connected to an external commutation reactor, then the braking unit must be connected to the line supply (diagram below). If the braking unit is connected downstream of the commutation reactor, then the inductance of the reactor prevents the braking unit from synchronizing on the line supply and generates overvoltag es, which can result in damage to the components of the braking unit.

CAUTION

RISKS OF INTERFERENCE

Overvoltages can cause serious damage to the frequency inverter and/or the braking unit and the other loads.

Failure to follow this precaution can result in equipment damage.

VW3A7...

Same warning about the presence, also not permitted, of other commutation reactors upstream of the braking unit.

60kW

1757361 11/2010 9

Checking the installation

ATV71

Line supply

VW3A7...

Line resistances and contact resistances

The values of the capacitive currents of the cables depend on the conductive material. This is relevant for sizing. Aluminum conductors must have a larger cross-section than copper conductors due to their high resistiv ity.

Whatever conductive material is used, the contact resistances of the connections must have a low impedance and the number of connections must be kept to the absolute minimum.

Too many connections or contact resistances that are too high can result in overvoltages during power generation.

Based on a stable line supply with for example a nominal voltage of 400 V with a return current of 80 A, and a connection with a contact resistance of 100 mΩ, a voltage dip of 8 V occurs (a correct connection has a contact resistance of approximately 1mΩ). During power generation if there are 7 connection points to the line supply, this results in a total voltage of 456 V.

10 1757361 11/2010

Checking the installation

60kW

ATV71

Line supply

VW3A7...

Prohibited

Correct

Connection of other loads

Connection of other loads (for example ventilation or air conditioning enclosure) in parallel on the frequency inverter and the braking unit with a common circuit-breaker is not permitted (see diagram below). If this is nevertheless performed, then if the circuit-breaker trips, the connection to the line supply will be absent (loss of power and synchronization information for the braking units). The IGBTs then transfer the DC voltage directly to the other loads. The resulting quasi-rectangular supply voltage signal sends a current across the loads, whose waveform and level depend on their impedance. If the power consumption of the loads is too low, then the DC vol tage and the output voltage of the braking unit increase during generation. This overvoltage can damage all the components that are connected.

1757361 11/2010 11

RISKS OF INTERFERENCE

Overvoltages can cause serious damage to the frequency inverter and/or the braking unit and the other loads.

Failure to follow this precaution can result in equipment damage.

CAUTION

Checking the installation

ATV71

Line supply

ATV71

VW3A7...

Connection of other loads (continued)

60kW

There are also risks of overvoltage for a structure such as that shown above. Even in this case, a circuit-breaker must be placed in each current return circuit.

Correction circuit without reactor

Correction circuits are used at the center of the line supply of a company. Interference and damage on these circuits have consequences on the line supply and can result in stoppage of the production process. Although they are no longer currently made, many correction circuits without reactor are in use. A wide variety of problems arise from the use of such correction equipment without reactor:

• Direct resonance

• Increase in resonance

• Switching transient

• Attenuation of central oscillations The fact that a company returns energy to the line supply is not the only reason for the creation of a resonance phenomenon. The power

of the medium voltage transformer cos ϕ correction unit is the decisive element. The higher this power, the greater the risk of resonance. The second important factor is the harmonic load of the medium voltage line supply.

This harmonic load is transmtted via the transformer and affects the low voltage level. More often than not the limits are exceeded by the 5th harmonic.

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