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4-2

The adjustments pertaining to the regulator and system operation are described in the following

paragraphs. These adjustments are made during initial operation and normally do not have to be

repeated during the life of the unit.

Stability Adjustment R4

This adjustment provides stable regulating operation. It controls the

amount of feedback that is applied to the error amplifier stage. Normally it is factory set in the 75%

rotation (CW) position. This setting normally assures good stability, but tends to slow the response

time of the generator. If rotated counterclockwise (CCW), the generator response time becomes

faster. However, if rotated too far CCW, the generator voltage may oscillate (hunt). It should then

be rotated CW well above the point where oscillating occurs. The system voltage instability is likely

to occur at no load. If a setting is desired that provides the fastest possible voltage response with

stability, an oscilloscope or some voltage recording device should be used.

Generator Voltage Adjust Rheostat R1

The adjustment is provided to control the generator

voltage. When adjusted to its maximum resistance position (CCW), minimum generator voltage is

obtained. Maximum generator voltage is obtained with minimum resistance (CW).

Nominal Voltage Range Set Adjust R3

This adjustment is provided to vary the limits of R1.

Normally R3 is set to provide R1 with an adjustment range of

10% of rated.

Before initial operation is attempted, verify that the regulator is connected for the proper application

as shown in either Figure 3-4 or 3-5.

The initial operating instructions are contained in the following paragraphs. These procedures

should be completely reviewed and understood, before system operation is attempted. Also, locat-

ing controls and adjustments pertinent to system operation would be beneficial.

Single Unit Operation (No Load)

a. Start the prime mover and bring up to rated speed. If a voltage shutdown switch is used

(see paragraph 4-3), close switch to apply excitation. When this switch is not used, genera-

tor voltage will build up automatically. (If field flashing is necessary, refer to paragraph 4-7.)

b. Verify generator voltage. (Any of the following conditions may occur.)

CAUTION

To avoid high voltage arcing, the field circuit must never be opened

during operation. Also a shutdown circuit using field discharge

resistors in the exciter field circuit should not be used. Safe shutdown

can be accomplished by interrupting regulator ac power to regulator

terminals 3 and 4.

4-4. ADJUSTMENTS

4-5. WIRING

4-6. INITIAL OPERATION

Basler SR4A User Manual

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