Motorvision Drawout (MVD) Technical Manual - PBSI Group Ltd

MVD TECHNICAL MANUAL
Air Circuit Breaker (ACB)
This starter type must be selected when the motor is controlled by a circuit breaker or
mechanically held contactor rather than an electrical held contactor regardless if the
motor is in actual fact a DOL starter.
Start A drives Output Relay 1 (CLOSE) to close the circuit breaker and start the motor
and Output Relay 2 (OPEN) is used to open the circuit breaker and stop the motor.
The operation of the CLOSE and OPEN relays is momentary (pulse type) and has a
programmable duration.
A Digital Input can be programmed to provide Circuit Breaker status feedback, Cont A is
renamed as ACB Feedback in ACB mode.
Direct On Line with Heater (DOLH)
This method of starting a motor is for applications where humidity / condensation causes
problems in motor windings. Direct on Line with Heater ‘DOLH’ avoids starting a motor
when the windings may be damp by energising Output Relay 2 (HEATER) whilst the
motor is stopped. In typically situations this output relay would control a contactor
feeding a heater embedded in the windings whilst the motor is stopped to evaporate any
condensation which may otherwise have developed in the motor.
This starter type is similar to Direct on Line ‘DOL’ where Start A is used to drive Output
Relay 1 (RUN) to control the motor in one direction only. Output Relay 2 (HEATER) is
used to control the Heater embedded in the windings or inject a current in the windings
whilst the motor is stopped. Output Relay 2 will automatically energise after 1 hour when
the motor is stopped and de-energise when the drive is started.
Direct On Line Reversing Heater (DOLRH)
This method of starting is the same as that above, but it is used with bi-directional
motors. Start A drives Output Relay 1 (FORWARD) to control the motor in the forward
direction and Start B drives Output Relay 2 (REVERSE) to control the motor in the
reverse direction. Output Relay 3 (HEATER) follows the same function as with DOLH.
Variable Speed Drive (VSD)
Variable Speed Drives allow precise control of the motor speed by varying the frequency
or applied voltage to a motor. By the very nature of variable speed drives the initial large
“inrush” current typically seen on Direct On Line started motors can be avoided. For all
other starter types (except VSD) the MVD requires the completion of a successful
starting sequence (i.e. the current must exceed 105%FLC and return to or below 100%
FLC before the motor is considered as running).
This starter type allows the MVD to consider the motor as running immediately after a
start signal has been issued. Start A drives Output Relay 1 (RUN) to control the motor
(which is assumed to be fed from an electrically held contactor).
The VSD starter type should also be selected for other starters which do not exhibit
inrush characteristics, such as soft starters.
For all Starter Types except VSD the successful completion of a starting sequence is
required before the motor will be considered running and protection features are
enabled.
It is recommended the CT’s fed into MVD are primary to the VSD inverter.
P&B Engineering Issue 1 03/2008 Page 37