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3E151 Set 1 V3
| Question | Answer |
|---|---|
| What is the main advantage of the melting-alloy type overload? | Amperage rating always stays the same |
| What does variable frequency drive (VFD) give an engineer? | Creates customer comfort and efficiency |
| Where would a feedback control source come from for a VFD? | Internal or External |
| Always do what to a VFD before attempting maintenance? | Verify unit is de-energized |
| On a magnetic line starter the control circuit consists of what items? | Holding coil, Auxiliary contacts, and overload relay reset contacts |
| What terminals are used to connect a three-phase motor to a magnetic line starter? | T1, T2, T3 |
| How many sets of main contacts does a single phase magnetic line starter have? | 2 |
| How are the contacts operated in a float switch? | Lever and float assembly |
| What is the thermostat sensitive to in heating and cooling systems? | Temperature |
| The hand, off, automatic switch is? | a three position switch |
| A relay may be defined as? | An electromagnetic switch |
| What is the function of a relay? | Open and close an electrical circuit |
| Normally speaking when comparing the load circuit to the control circuit in a relay | The load circuit is shorter and made of a heavier conductor |
| The power Supply is attached to what part of the motor? | Stator |
| Where is electrical energy converted into mechanical energy in an electric motor? | Rotor |
| What is the purpose of the skew effect on a squirrel cage motor? | Increases the torque |
| Current Flow in the stator is transferred to the rotor of a three phase motor... | by magnetic induction |
| What is one way to connect a three phase motor for 440 volts? | Wye, Series |