Author Question: When do normally closed relay contacts close? A) When the relay coil is de-energized B) When the ... (Read 316 times)

ENagel · **on:** Jul 27, 2018

When do normally closed relay contacts close?

A) When the relay coil is de-energized
B) When the relay coil is energized
C) When they receive power
D) They are always closed because they are closed contacts.

Question 2

A heat recovery ventilation system saves energy by:

A) Decreasing the size of the indoor air-conditioning system blower.
B) Preheating the ventilation supply air with electric heat strips.
C) Exchanging heat between the supply and exhaust air streams.
D) Preheating the ventilation exhaust air with electric heat strips.