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Second Period Electrician > Reversing Motor Starters > Flashcards

Flashcards in Reversing Motor Starters Deck (14)
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1
Q

how many contactors does a reversing magnetic motor starter require?

A

two

2
Q

how many power contacts are needed for a basic reversing magnetic motor starter?

A

six

3
Q

the forward holding contacts for NEMA are numbered ___ and ____

A

2 and 3

4
Q

the forward holding contacts for IEC are numbered ____ and ____

A

13 and 14

5
Q

the reverse holding contacts for NEMA are numbered

A

4 and 5

6
Q

the reverse holding contacts for IEC are numbered

A

13 and 14

7
Q

why is mechanical interlocking required on a reversing magnetic motor starter?

A

to prevent short circuits

8
Q

how is mechanical interlocking between armatures achieved?

A

physical linkage between the two

9
Q

why are electrical interlocks used on reversing magnetic motor starter?

A

to prevent coil burnout

10
Q

how is electrical interlocking achieved?

A

achieved by placing NC contacts controlled by the reverse coil in series with the forward coil and vice Versa

11
Q

what is the purpose of holding contacts?

A

to keep the coil energized after the start button is released

12
Q

a reversing magnetic starter employs ___ sets of holding contacts

A

2

13
Q

what is the number labeling of the holding contact terminals on a NEMA starter?

A

2/3 and 4/5

14
Q

identify the seven sections in the control circuit of a forward/reverse magnetic that contacts of control relays or pilot operating device contacts could be placed

A

general stop, forward stop, forward start, forward holding, reverse stop, reverse start, reverse holding