Toshiba GRL150-100 Series Instruction Manual page 146

Note: When a failure or an abnormality is detected during the regular test, confirm the following
first:
- Test circuit connections are correct.
- Modules are securely inserted in position.
- Correct DC power voltage is applied.
- Correct AC inputs are applied.
- Test procedures comply with those stated in the manual.
6.7.3 Replacing Failed Relay Unit
If the failure is identified to be in the relay unit and the user has a spare relay unit, the user can
recover the protection by replacing the failed relay unit.
Repair at the site should be limited to relay unit replacement. Maintenance at the component level
is not recommended.
Check that the replacement relay unit has an identical Model Number and relay version (software
type form) as the removed relay.
The Model Number is indicated on the front of the relay. For the relay version, see Section 4.2.5.1.
Replacing the relay unit
CAUTION
After replacing the relay unit, check the settings.
The procedure of relay withdrawal and insertion is as follows:
• Switch off the DC power supply.
WARNING
• Disconnect the trip outputs.
• Short-circuit all AC current inputs.
• Unscrew the relay front cover.
• Unscrew the binding screw on the handle.
• To remove the relay unit from its case, pull up the handle and pull the handle towards you. (See
Figure 6.7.1.)
• Insert the (spare) relay unit in the reverse procedure.
CAUTION
To avoid risk of damage:
• Keep the handle up when inserting the relay unit into the case.
• Do not catch the handle when carrying the relay unit.
• Check that the relay unit and its case have the identical Model Number
when inserting the relay unit.
Hazardous voltage may remain in the DC circuit just after switching off the
DC power supply. It takes about 30 seconds for the voltage to discharge.
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