Rockwell Automation MinPak Plus DC Drives Kits User Manual

Page 25

181

CIRCUIT

BREAKER

1CB

2CB

CURRENT

FEEDBACK

TO REGULATOR

182

MOTOR

ARMATURE

POWER UNIT #1

POWER UNIT #2

Figure 5.2 - Full Wave Regenerative Bridge Configuration

5.4 PowerCircuit Malfunctions Ċ The power circuit Is

protected against malfunctions. The peak overload

conditions which may be caused by a mechanical jamĆ

ming of the motor shaft are guarded against by the curĆ

rent limit function and the POWER ON/OFF circuit

breaker.
Peak operating overloads such as those experienced on

acceleration, shock loading, etc., are guarded against by

a fastĆacting, currentĆlimiting circuit in the regulator.
In the event of an inverting fault caused by an aĆc line loss

or dip, damaging high peak currents are protected

against by a singleĆpole circuit breaker in the dĆc armaĆ

ture circuit (3CB in Figure 5 2).

Figure 5.3 - Power Cube

5.5 Transient Protection Ċ The controller's internal

Power Cube thyristors are protected from aĆc line voltĆ

age surges by a metal oxide varistor (MOV) surge supĆ

pressor connected directly across the aĆc line. (Refer to

Figure 5.2.) The MOV is available as a replaceable modĆ

ule in case its energy absorption rating is exceeded. An

RĆC network is connected across the dĆc output of the

Power Units. This network prevents ''ringing" in the arĆ

mature circuit caused by various motors and dĆc line

voltage spikes. Four additional RC circuits protect indiĆ

vidual thyristors from false firing due to noise spikes.

These RC circuits along with the output RC circuit are

contained on the DV/DT Module.
5.6 Field Supply Ċ The optional Field Supply Kit is

available for use with Regenerative MinPak Plus controlĆ

lers used with motors rated at 1/4 thru 5 hp. The Kit is

standard on controllers for 2 to 5 hp applications.
The Field Supply is a constantĆpotential rectifier consistĆ

ing of four diodes. This configuration provides 100 VDC

from a 115 VAC power source. It also provides 200 VDC

from a 230 VAC power source. Half wave (half voltage)

is available. (Refer to Figure 6.12.)
The Field Supply is protected by the MOV surge supĆ

pressor.
5.7 RegulatorModule Ċ The Regulator Module, a

standard component of each Regenerative MinPak Plus

controller, is discussed with respect to functions and deĆ

scriptions.
5.7.1 Functions Ċ The Regulator Module provides maĆ

jor and minor loop regulation, thyristor gate firing and seĆ

quencing. It also provides protective functions for the

eight thyristor power modules.