A652-18-880 Issue C
Page 16
© Edwards Limited 2008. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
INSTALLATION
5.3.3
Connection of additional thermal protection devices
5.3.3.1
RV3, 5, 8, 12 and E1M/E2M18 and E2M28 pumps
The thermal trip (open when overheated) located in the motor terminal box, must be connected to a circuit breaker,
which prevents the pump from restarting once a fault condition has occurred.
5.3.3.2
EM40/80 pumps
No additional thermal protection devices are required.
5.3.3.3
EM175/275 pumps
The external thermal snap switch located on the body of the pump, must be connected to an intrinsically safe circuit
in accordance with EN50020 Electrical apparatus for use in potentially explosive atmospheres - Intrinsic safety "i" for
use with simple apparatus suitable for the classification of the hazardous zone in which the pump will be located.
If this is not possible, the circuit should be placed in a safe zone.
5.3.4
Check the direction of rotation
CAUTION
Ensure that the pump-motor rotates in the correct direction. If it does not, the pump and your vacuum system
can become pressurised.
1. Correct direction of rotation is anti clockwise when looking on the motor fan.
2. Watch the motor fan, switch on the supply to the motor for a few seconds, and then switch off.
3. If the direction of rotation is incorrect, isolate the motor from the supply and reconfigure the electrical
connections to the motor; refer to the manufacturer’s recommended installation instructions supplied with the
motor.
4. Repeat the above check to ensure the direction of rotation is correct.
