Relays; Construction; Operation; Trouble Shooting - Wascom EMERALD W75ES Operating & Maintenance Manual

Relays

The Wascomat Emerald series models employ
Fig.
three relays. The relays control:
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• the reversing wash of the wash motor (1,2)
• the extraction motor (3)

Construction

The body of the relay holding the stationary
Fig.
contacts is made of current-resistant plastic. A
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solenoid and a contact bank hold the moving
contacts. The contacts are spring-loaded to
assure the correct contact pressure.
The relay is constructed for continous operation,
whether mounted horizontally or vertically.
Screw-type terminals provide perfect connections
even when one or two wires have different dia-
meters.

Operation

When the solenoid is energized, the two halves
of the magnet core are drawn together, pulling
down the moving contacts, thus making or brea-
king the circuit. When the current cuts out,
springs force the contact bank into its original
position, thus closing or opening the circuits.

Trouble shooting

If the relay fails to operate despite power to the
coil, turn off the power and check the solenoid by
measuring the resistance across the terminals
(1).
If the relay hums when power is applied, this
indicates either a break in the insulator holding
the moving contacts at the axle where it holds the
top half of core (3) or a rusty core (4), which can
be cleaned.
Make sure that the moving contact assembly
moves freely. Always replace burnt or pitted
contacts (2) ... do not reuse contacts.
Mechanical and electrical design
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