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Normally the machine is supplied from one side of the stator winding only and the other side is isolated connected in star or delta. Open-end winding means the neutral point of the machine is opened and now the supply is possible from both side of the stator winding of the machine.
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At what approximate percentage of the normal run speed is the start winding disconnected from the circuit?
The centrifugal switch on a motor's start winding should open at 75 to 80 percent of the motors run speed RPM.
Can alternating current be switched using normally open switch relays?
Yes. In fact, induction motor 'starters' work using normally-open relays, controlled by low-current control circuits -although we call these heavy-duty relays 'contactors'.
What speed does a centrifugal switch open and disconnect the start winding?
Aprox 75%
What happens when secondary of the transformer is open?
The secondary winding leakage inductance limits the current during a short. It seems that the current through the primary is limited by winding resistance and leakage resistance when the secondary is shorted.
Should a motor with a start capacitor have a start relay?
The compressor motor employs both a start and run winding. The run winding is energized during the complete cycle of operation, whereas the start winding is energized only during the starting period. The current-operated type of relay has a coil connected in series with the run winding of the compressor. Some current-operated relays plug directly onto the compressor while others do not. Most relays are mounted in a case located on the compressor. When the thermostat closes, the compressor attempts to start, drawing heavy current through the run winding and the relay coil. This strong current flow through the relay coil creates a magnetic field strong enough to cause the start contacts to lift and close, energizing the start winding. When the compressor reaches approximately 3/4 running speed, the current flow through the relay coil decreases (due to the countering electrical magnetic field in the motor) and as the magnet weakens, the start contacts fall open. This type of relay must be used with an overload protector and must be mounted in an upright position, so that the contacts can fall freely to the "open" position.
What is the useful of open end winding of induction motor?
Standard induction motor has a closed squirrel cage rotor, where as open ended induction motor has split phase rotor.
What are the advantages of open end winding induction motor over conventional induction motor?
Open ended induction motor - i assume you are talking about split phase induction motor. With these motors old style speed controlling method using external resistors can be used. However this is now obsolete.
What happens if field winding of a running dc shunt motor suddenly breaks open?
when the field winding of a running dc shunt motor suddenly breaks open the motor fails to run because in the motor the stationary winding is armature and rotatory is field winding
What is the use of centrifugal switch in single phase induction motors do all single phase motors gave them?
To stop a three-phase motor dead ('plugging'), rather than allowing it to slow to a stop, the motor controller interchanges two of the three lines -which applies a reverse torque to the machine. But before the motor then gets a chance to reverse direction, the centrifugal switch trips the starter and removes the supply. <<>> The centrifugal switch that you refer to and can see in an open frame motor, is used to open the start winding of small HP single phase motors. Once the motor gets up to a certain RPM, the switch opens and the motor continues to operate on its run winding. When the motor stops, the switch goes back to its normally closed position in the start winding and awaits the next start operation.
What is used on a single phase induction motor to disconnect the start winding after the motor starts?
A centrifugal switch, once the motor reaches near run speed, centrifugal force causes a set of contacts to open and disconnect the start capacitors. Some larger motors use a contactor which is disconnected by the centrifugal switch.
What meter is used to bench check a motor for short or open winding?
Ohmmeter
How would a motor that has an open run winding react at starting time hvac?
Nothing
What is open phase in induction motors?
The field windings of a three-phase motor are termed 'phase windings'. An 'open phase' means that one of these windings has become open-circuited -i.e. there is a break in the winding. Unfortunately, however, 'line conductors' are often incorrectly referred to as 'phase conductors', so a break in a line conductor could (incorrectly) be called an 'open phase'!
What happens if you short the shunt windings of a motor?
Answer:If the shunt winding is open the motor won't start, but if the shunt open while the motor is running, the motor will keep on running as if nothing went wrong, except if the wire of the winding get maniacally between the stator and the fields the motor can be damaged beyond repair. But normally the shunt windings is done with very thick conductors, so the chance that the shunt will go open is zero.
What can a split phase motor use to energize and deenergize the start winding?
A split-phase motor uses a centrifugal switch to energize and de-energize the start winding. The switch is connected in series with the start winding circuit and is typically set to open when the motor reaches about 75-80% of its operating speed, disconnecting the start winding from the power supply.
What happens when a motor only has voltage no current?
Power is voltage times current. If there is no current, then there is no power. Without power, no work can be done, so the motor will do nothing.In all probability, if this is happening to a motor, then there is an open circuit someplace, perhaps an open winding.
At what approximate percentage of the normal run speed is the start winding disconnected from the circuit?
The centrifugal switch on a motor's start winding should open at 75 to 80 percent of the motors run speed RPM.
