0
Why does a star delta motor run at a very slow speed on delta after changing from star to delta?
Wiki User
∙ 14y ago
There could be several different reasons for a motor to run slower than it should do after it has been switched over from star to delta connection.
Here are some possible reasons, but there may be others:
- its star-delta starter unit has a fault or has some bad external connections
- a broken or disconnected phase winding (or windings) inside the motor's frame.
<><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Wiki User
∙ 14y ago
Add your answer:
Earn +20 pts
How speed increases when flux decreases in dc shunt motor?
Increasing flux, torque of the dc motor will be increased and speed of the dc motor will be decreased as speed of the dc motor is inversely proportional to that of the flux and the torque of the dc motor is directly proportional to the flux.
Would it be correct to say with a fixed field voltagethe speed of a shunt motor is proportional to its armature voltage?
With increasing torque load the armature tends to slow down; the motor draws more current to compensate, and if there is armature resistance the back emf generated by the armature falls to allow the increased current to flow, which causes the motor to settle at a lower speed. The mechanical output power is the speed times the torque, and increasing the torque increases the power output provided the speed does not drop much.
Does the RPM of a motor vary if a load is added to the motor?
The speed of an electric motor is directly proportional to the frequency of supply. The rpm written on the name plate is the maximum operating speed for the motor design. Typically, for a squirrel cage induction motors, the speed is constant by design and this type of motor cannot operate for a long time at speeds below the rated value. It is true that loading affects motor speed to some extend but the electric motor will accelerate to the rated speed. If the loading is within the design parameters of the motor, the electric motor speed will not drop. What typically happens is that if the loading increases, the speed goes down, and the current increases. Because voltage is constant, this result in a high I2R loss in the windings and the motor circuit protection trips on thermal and electrical overload. The formula for electric motor speed is SRPM=(120f)/P. The above is for AC motors. If you are referring to a DC motor, what you have stated is correct. The motor will slow down as load is added. That is why you are not supposed to run many DC motors under no load conditions - they will overspeed.
Why elevators run on direct current?
One of the requirements of an elevator is high speed between floors, but a slow speed as it approached the floor, so that the floor levels are accurately aligned. This is easy to organize with a DC motor.
How do you change AC motor speed?
A change in frequency of the motor will cause a change in the speed of the AC conveyor motor. This frequency change is brought about by a device called a Variable Frequency Drive. It is used to vary the frequency of the motor from 0 to 100%. I have no idea what the second answer is talking about. ANSWER: considering that no mention of type of motor is involved the frequency change theory is quite invalid since 50 or 60 Hz AC line runs clocks from banks to wake up calls and while it is true that the frequency is not accurate from second to second it is however very accurate from minutes to minutes.
How is the speed of an AC motor that's being driven by a constantly changing sine wave voltage effected?
Assuming the sine wave's angular frequency is what's changing, the motor will speed up and slow down in proportion to that frequency.
Can you slow down the bicycle by changing the gear?
No. Simply changing the gear without doing anything else won't slow a bicycle down. You can coast along without peddling and that will slow you down or you can use the brakes to slow the bike. Changing gears will affect the speed only if the current speed is slower than the highest speed you can reasonably attain with the selected gear - changing to a higher gear will help you speed up.
How do you reduce the speed of a 15 kW 3 phase motor without using variable speed control?
If the load is connected to the motor via belts, you can change the speed the load is turning by changing the pulley sizes. To get the load to slow down, increase the size of the pulley on the load; to get it to speed up, increase the size of the pulley on the motor. To reduce the speed of the motor itself, you'll have to alter the line frequency, which you can't do without a variable frequency drive attached to the motor.
Why is your car making a grinding noise when you have the AC or heat on and you brake to slow the car and or give it gas?
It is probably a worn blower motor, because it happens with AC, and/or HEAT. When you brake or speed up, you are changing the speed of the motor (adding and taking away resistance to it's spinning). This will cause more of a noise until you reach your cruising speed again.
How do you know if the starting motor is failing?
Good battery,slow cranking speed ,noisy,
Is Delta a fast change or a slow change?
You're going to need to be a lot more specific. Mathematically and scientifically, delta is the symbol for change, period, without specifying anything about whether it's fast or slow.
How do change the speed of a chain driven conveyor?
if you can't change the RPM of the motor, you have to change the gearing of the chain drive. Fit a smaller sprocket to the motor to slow the conveyor down, or a bigger to speed it up.
How two speed motor work?
there is two winding is there, one for slow speed , another for fast speed, but both are not variable, but is constant speed. If you use inverter, High speed wingding used for inverter connection .
Specification of a dc motor?
DC Motor Specifications: 1.RPM 2.No-heap Speed 3.Slow down Torque 4.Most extreme Current
What is an area of slow stream speeds?
A delta
What is associated with slow wave sleep?
Delta
Why would your blower fan resister stop working?
Because for each speed except the higgest one, to slow the motor of the fan, a resistor is choose and it's a big resistor, bigger to slow the speed and after long use or if the motor is defect (use to much currant), the resistor burn and no currant can pass trough
