Page 252 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Power control relays
Although the previous relays are also used in control panels, the so-called control relay uses a slightly different
operating principle and is specifically designed to switch the higher powers found in control panels.
• There are a number of shapes and sizes but most are similar to those shown here.
• They can be either flush-mounted to the chassis or DIN rail-mounted.

• There are at least 3 sets of contacts in the main body with a wide range of contact combinations available.
• In addition there are auxiliary contact sets which are clipped to the sides and in some cases to the top of the
main body.
• The connections are made with screw clamp terminals.

• The contact and coil terminals are at the front and are shrouded to stop fingers touching live connections.

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CITS : Power - Electrician & Wireman - Lesson 93-100