030205e

Card Set Information

Author:
PBJay
ID:
60088
Filename:
030205e
Updated:
2011-01-16 14:25:58
Tags:
magnetics
Folders:

Description:
Construction of Magnetic Motor Starters/Overload Devices 030205e
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  1. The size of the overload device on a motor magnetic would be determined by the starting current of the motor.

    True False
    True
  2. A three phase motor magnetic starter must have an overload heater in each phase.

    True False
    True
  3. 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
  4. A standard motor magnetic consists of a contactor and an overload device.

    True False
    True
  5. Holding contacts are connected:
    A) both "B" and "D" apply
    B) in series with the start button
    C) in parallel with the start button
    D) in parallel with the operating coil
    E) directly in series with the stop button
    C) in parallel with the start button
    (this multiple choice question has been scrambled)
  6. Magnetic overloads are said to be:
    A) heat dependant
    B) instantaneous
    C) time lag
    D) none of the above
    B) instantaneous
    (this multiple choice question has been scrambled)
  7. 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
  8. 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
  9. The rule in Section 28 of the C.E.C used to determine the AMPACITY of overload heaters for motor controllers would be:
    A) 28 - 308
    B) 28 - 302
    C) 28 - 304
    D) 28 - 306
    D) 28 - 306
    (this multiple choice question has been scrambled)
  10. The NEMA numbering for the terminals of the holding contacts are 1 and 2.

    True False
    False
  11. The two basic principles of operation used for overload protection devices in a motor circuit are thermal and electromagnetic.

    True False
    True
  12. It is possible to order a bi-metal thermal overload device with ambient temperature compensation.

    True False
    True
  13. According to the C.E.C., only two overload heaters are required for a three phase motor.

    True False
    False
  14. "Holding" contacts are used as a by-pass of the:
    A) operating coil
    B) start button
    C) motor contacts
    D) overload heaters
    E) more than one of the above apply
    B) start button
    (this multiple choice question has been scrambled)
  15. A motor magnetic is a:
    A) contactor with overload devices
    B) relay with overload devices
    C) contactor
    D) both "A" and "B" apply
    E) all of the above apply
    A) contactor with overload devices
    (this multiple choice question has been scrambled)
  16. There are two types of thermal overload devices. These are the bi-metal and the melting alloy type.

    True False
    True
  17. When a motor magnetic starter is used on a higher voltage the hp rating of the starter is increased.

    True False
    True
  18. 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:
    A) the overload heater is burnt out
    B) coil needs replacing
    C) the contacts are faulty
    D) everything is normal
    E) the wiring in the starter is faulty
    D) everything is normal
    (this multiple choice question has been scrambled)
  19. 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:
    A) the overload heater is burnt out
    B) coil needs replacing
    C) everything is normal
    D) the contacts are faulty
    E) the wiring in the starter is faulty
    A) the overload heater is burnt out
    (this multiple choice question has been scrambled)
  20. The NEMA numbering for the terminals of the holding contacts are 2 and 3.

    True False
    True

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