Page
14
Model
1000
Installation and Operation Manual
6/1/2001 © copyright 1997 by Powertec
CONTACTOR SPECIFICATIONS
If you want to operate an Output or Dynamic Braking Contactor
directly from the Model 1000 or 1000A, you must choose a coil that
draws less than 50 milliamps DC.
The Output Contactor drawing on page 15 shows the
connections for direct operation of the contactor (use the same
connections for Dynamic Braking). The coil must be 48VDC and
draw less than 50 ma DC (2.4 Watts). This is the most power
available from the Model 1000 series drive’s supplies.
To use a 115VAC or 230 VAC coil, you need a 156-012
Contactor Control board, as shown in the drawing on page 15. Use
the same drawing for the Output Contactor. Maximum current for the
Contactor Control board is 1 Amp at 230 VAC.
You need three normally open power poles and a normally open
auxiliary for an Output Contactor. The contactor does not make or
break with current in the power contacts. Choose the contact ratings
only on the basis of carrying the current.
For Dynamic Braking, you need three normally closed power
poles and a normally open auxiliary. The contacts make with current
present, but they do not break current in the dynamic braking
operation. Choose contacts accordingly.
The contactor outline sketched at left is from the SH-04 series by
AEG Industries. The model used for the Output Contactor is part
number SH-04.40 and the Dynamic Braking is SH-04.13. Contact
ratings are 16 Amps.
DYNAMIC BRAKING RESISTORS
We choose DB resistors for their ability to absorb high inrush currents and to accept large amounts of
power for short periods of time. Typical DB resistors can absorb ten times their power rating for up to five
seconds. The resistors must then cool down to ambient temperature before they can dissipate their full rating
again (usually a few minutes). It is possible to extend the ratings by about three times with power resistors by
forced-air cooling.
You can derive an approximate value of dynamic braking resistor from the bus voltage and the full load
current on the nameplate of the motor:
Bus Voltage X 0.47
Each Resistor Value ~ -----------------------------------
Motor FLA
Three resistors (or groups of resistors) are necessary. The power rating of each should be:
Power > 0.02 X (Buss Voltage)
2
/ (Resistor Value)
These formulas are very general, and results will vary from motor to motor. For dynamic braking tailored
to your application, consult
Powertec
Engineering.
1.77"
1.66"
13 21 31 41
A1
14 22 32 42 A2
TOP VIEW
BOTTOM VIEW
1.25"
0.19"
1.54"
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