Reversing Motor Starters Flashcards
how many contactors does a reversing magnetic motor starter require?
two
how many power contacts are needed for a basic reversing magnetic motor starter?
six
the forward holding contacts for NEMA are numbered ___ and ____
2 and 3
the forward holding contacts for IEC are numbered ____ and ____
13 and 14
the reverse holding contacts for NEMA are numbered
4 and 5
the reverse holding contacts for IEC are numbered
13 and 14
why is mechanical interlocking required on a reversing magnetic motor starter?
to prevent short circuits
how is mechanical interlocking between armatures achieved?
physical linkage between the two
why are electrical interlocks used on reversing magnetic motor starter?
to prevent coil burnout
how is electrical interlocking achieved?
achieved by placing NC contacts controlled by the reverse coil in series with the forward coil and vice Versa
what is the purpose of holding contacts?
to keep the coil energized after the start button is released
a reversing magnetic starter employs ___ sets of holding contacts
2
what is the number labeling of the holding contact terminals on a NEMA starter?
2/3 and 4/5
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
general stop, forward stop, forward start, forward holding, reverse stop, reverse start, reverse holding
