OUTPUT C!RCUiTRY

The output amplifier produces either positive or negative signals tO drive the regulator 0 r exciter (as

required). The polarity of this signalis determined by the appropriate jumpering ofthe A-B Polarity

Fanning Terminal Strip.

OVER-ÉXCITATION LIMITINGD

a. Over-excitation limting provides an initial fast actlng limlt of the current at a pre-selected

high level (allowing for motor-starting, fault clearing, etc.). After a set period of time (Oto 60 sec-onds),

the limit will drop to a lower level to prevent field overheating.

b. The dc current output Of the exciter or regulatorwlll pass through a the dc transducer (T3 ) .

The ac output of T3 will always be proportional tO the input  This ac output is rectified,

adjusted and applied the lnverse Timer.

0 If an inverse time characteristic destred the lnverse Time Adjustment is set for th 巳 desired

time and the Fixed Time Adjustment set counter-clockwise (CCW) 10 zero time- Figure 2 . 2

illustrates the inverse time characteristics for three dlfferent settlngs Of the lnverse Time Adjustment

(fully CW Mid-Range. and fully CCW)

d. If fixed time characteristic is desired or required, the lnverse Timer is set fully CCW tO zero

time, while the Fixed Timer is set the desired time. After the selected timer has timed out, the

e current becomes limited at the delayed threshold limit.