The size of the overload device on a motor magnetic would be determined by the starting current of the motor.
True False
True
A three phase motor magnetic starter must have an overload heater in each phase.
True False
True
Magnetic overloads are made adjustable by physically moving the armature in or out of the magnetic field produced by the motor current.
True False
True
A standard motor magnetic consists of a contactor and an overload device.
True False
True
Holding contacts are connected:
D) in parallel with the start button
Magnetic overloads are said to be:
C) instantaneous
The purpose of the holding contacts on a motor magnetic is to keep the coil energized after the start button has been released.
True False
True
When the armature of a motor magnetic is pushed in by hand, a continuity test between terminals 2 and 3 shows zero ohms. This is an expected reading.
True False
True
The rule in Section 28 of the C.E.C used to determine the AMPACITY of overload heaters for motor controllers would be:
C) 28 - 306
The NEMA numbering for the terminals of the holding contacts are 1 and 2.
True False
False
The two basic principles of operation used for overload protection devices in a motor circuit are thermal and electromagnetic.
True False
True
It is possible to order a bi-metal thermal overload device with ambient temperature compensation.
True False
True
According to the C.E.C., only two overload heaters are required for a three phase motor.
True False
False
"Holding" contacts are used as a by-pass of the:
B) start button
A motor magnetic is a:
C) contactor with overload devices
There are two types of thermal overload devices. These are the bi-metal and the melting alloy type.
True False
True
When a motor magnetic starter is used on a higher voltage the hp rating of the starter is increased.
True False
True
When the armature of a motor magnetic is held in the closed position, a continuity test between L(2) and T(2) indicates zero ohms. This is most likely a sign that:
B) everything is normal
When the armature of a motor magnetic is held in the closed position, a continuity test between L(1) and T(1) indicates an open circuit. This is a sign that:
B) the overload heater is burnt out
The NEMA numbering for the terminals of the holding contacts are 2 and 3.
True False
True
Author
PBJay
ID
60088
Card Set
030205e
Description
Construction of Magnetic Motor Starters/Overload Devices 030205e