Richards 137NP, Инструкция по эксплуатации, Страница: 21 / 53

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Figure 4 shows a test set up for obtaining the various voltages required for testing the
protector mechanism. The variable auto-transformer should have inputs of 208 and 460 volts
with a 16 amp current rating.
Figure 4 – Single Phase Test Circuit
F. Checking the Minimum Tripping Voltage
Using the auto-transformer test set up as described in Figure 4 apply 16 volts to studs K and
L on 125/216V units and 36 volts to studs 11 and 21 on 277/480V units. Connect the
tripping contact of a control switch across terminals 1 and 3 (wire No. 41-11) of the master
relay plug. Activation of this contact should trip the protector.
G. Checking the Minimum Motor Closing Voltage
Using the auto-transformer test set up as described in Figure 4, apply 157 volts to studs K
and L on 125/216V units and 200 volts to studs 11 and 3A on 277/480V units. Connect the
closing contact of a control switch to terminals 2 and 3 (wire No. 6-11) of the master relay
plug. Close the motor relay by hand by lifting up the plunger. Activate the closing contact
of the control switch. The motor should close the protector. There is no adjustment for
minimum closing voltage. This test merely shows that the motor has sufficient torque to
close the protector.