The advantage of mercury relays is that each time the relay is used the contact is renewed, eliminating burning and pitting caused by an arc when connection is made or broken.

Figure 11-6 The accompanying figure shows a bellows-operated ____________________ timer.

Magnetic reversing starters generally change T leads ____________________ and ____________________ to reverse the motor.

  The contact symbols in the above diagram indicate _______________________________.

How can the direction of rotation of any three phase motors be reversed?

____________________ diagrams show electrical components in their electrical sequence without regard for physical location.

The contact symbols in the above diagram indicate _______________________________.

True/False Questions

There may be times when it is desirable to have more than one START–STOP push button station to control a motor.

Many bimetal strip type overload relays can be set for either manual or automatic reset.