Vanguard MCCB-250 User Manual

Page 14

MCCB-250 USER’S MANUAL

REV 2

Use the steps below to test the time delay of a protection relay:

a. Connect the Safety Ground to the MCCB-250.

b. Connect the AC power cord.

c. Connect the Current Cables from the MCCB-250 to the bus as shown in Figure 3.

d. Connect the

[TIMER STOP]

cables as shown in Figure 3.

e. Turn the

[CURRENT CONTROL]

knob to zero.

f. Turn on the

[POWER SWITCH]

g. Select the DRY CONTACT mode for the

[TIMER STOP]

input by pressing the

[LEFT

ARROW]

key until the DRY CONTACT LED light is illuminated.

h. Hold the

[DOWN ARROW]

key to momentarily turn on the current source. Note that

the HIGH CURRENT PRESENT LED will be illuminated.

i. Turn the

[CURRENT CONTROL]

knob to set the desired current.

j. Release the

[DOWN ARROW]

key.

k. Press the

[UP ARROW]

key to select the ON+TIMER mode and start the test. The

MCCB-250 will inject the preset current into the bus and turn on the timer. The timer
will stop and the current source will be turned off when the MCCB-250

[TIMER STOP]

input detects a change in the relay dry contact. A typical MCCB-250 time delay test
results screen is shown below:

NOTE

In the above test, the timer will be stopped and the current source turned off
by a change of state in the

[TIMER STOP]

input or when the operator

presses the

[DOWN ARROW]

key to select the OFF mode. If the test is

aborted by the operator, no timer or current information is displayed.

986 mS 59.2CY

Ext I:+0.000 A
Drv I:20.00A