11.
12.
13.
14.
Reconnect the signal source connections removed in step 7.
Turn the signal source and the DCR-B power ON.
Set the signal source for 400 mV output.
Vary the signal source output slightly until the rated full scale de out
put current of the DCR-B is obtained. (e.g., DCR-40-13B may require
385 mV for 13A output).
- -
15.
Using output voltage obtained in step 13 to calculate the program con
stant (Amps output per control supply input). For example: Assume
that a voltage of 385 mV is required to obtain a full 13A output. The
fbrmula would be as follows:
PROGRAM CONSTANT = DCR-B Amps Out
= Amps/mV
Signal Source mV Out
(e.g ·) 13A - 0 0338 Amps/mV
385 mV-
16.
Remove DCR-B output short.
Overvoltage from the signal source will only produce 115% of rated output current.
3 .4
PARALLEL OPERATION
DCR-B single phase units may be paralleled using either of two methods. One
method uses a master /slave approach, and the other involves direct paralleling.
Each method has its advantages. In master/slave operation the output voltage
regulation is maintained, but only four units may be paralleled; with the direct
method, there is no limit to the number of units which may be paralleled and no
current derating is required. Output voltage regulation, however, does deterio
rate.
3.4.1
Direct Paralleling (Figure 3-8)
The following steps outline the procedure for connecting two units in parallel (the
same procedure may be extended to parallel as many units as desired):
1.
At no load, adjust individual unit voltages to desired system output.
Attempt to match individual unit outputs with FINE VOLTAGE controls.
2.
Set power on each unit to OFF, and run load leads from units to load.
Observe Polarity.
3.
If remote sensing is to be used, connect sensing leads from units to
load, also observing polarity. Use twisted wire or shielded pair for
leads.
4.
Set each unit POWER switch to ON.
'.fhe �nit supplying the highest voltage will supply the load, as it is impossible to
identically match the output voltages. If the load requirements exceed the setting
on the CURRENT control, this unit will automatically cross over to current
mode operation, and its output voltage will drop. The second unit will then
assume that portion of the load rejected oy the first. Any further increases
Operation
3-12
Rev B (6/84)
