Operation

To put the 515 Blocking & Test Module into operation, additional parts have been provided:

• 1 package containing at least 28 terminal nuts

• 14 white tags for identification of each of the switches

The 515 provides a means of trip blocking, relay isolation, and testing of GE Multilin relays.

The 515 accomplishes this with a total of 14 switches. There are 6 single pole throw

switches for use with the output relays, and 4 groups of 2 switches each for use with the

current transformers as illustrated in Figure 1: Typical Wiring.

Isolation or opening of the relay’s output circuits is accomplished with the six switches

at terminals 1 through 6 and 15 through 20. These switches can be used to simply open

the protection relay’s output contacts and thus provide a means of blocking trips.

The 4 remaining groups of 2 switches at terminals 7 through 14 and 21 through 28 are

used for shorting of the CT inputs, injection of test current, and measuring of CT current.

The four groups correspond to Phase 1 Current, Phase 2 Current, Phase 3 Current, and Ground Current.

Each group is made up of two switches. The first switch for the Phase 1 group is at

terminal 7 and 21 and is configured as shown on the right:

Note that terminals 7 and 21 are shorted together regardless of whether the switch is open or closed.

The second switch for the Phase 1 group is at terminals 8 and 22. It is configured as shown on the right:

Note that this switch operates as make before break. When this switch is closed terminals 8 and 22 are

shorted together.