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Phase Guard Relay Test Procedures

1. Carefully remove any one (1) of the three inputs phases or fuses connected to the Phase Guard relay terminal strip. (Warning: extreme caution should be used due to the high voltage carried on these lines).

2. When any one phase is removed the time delay cycle begins immediately. After the proper time delay has elapsed the output relay should change state, (pickup or drop out) depending upon the model being tested.

3. Re-connecting the missing phase should cause the unit to reset to its normal state immediately.

4. Repeat this procedure on each of the remaining two phases.

Trouble Signs

The Phase Guard relay is an extremely reliable and durable device, but under certain conditions they can be damaged. Should you experience any of the following conditions, there is a good possibility that the Phase Guard is defective:

1. A defective unit may tend to nuisance trip frequently. This will generally occur without any indication of a serious phase loss or phase unbalance condition being present.

2. If the red (reverse phase) led is lighted when no reverse phase exists, it is likely that the unit is defective.

3. A defective Phase Guard may be reluctant to reset to its normal position after normal 3 phase power has been restored and all phases are balanced.

4. In testing, if any one (1) phase is removed and the unit trips immediately, without cycling through the normal time delay the unit is likely defective.

A defective Phase Guard may be repairable. We will evaluate all units at no charge, and call with an estimate before beginning any repair work. When repaired, the units are automatically updated to present specifications and are reliable for either primary or backup service.