What are the reasons of rotation with low speed even if the full 220 V is applied
1) Reduction in supply voltage
2) Reduction in supply frequency
3) Increased blade angle than designed value (mechanical loading increased)
4) Wrong value of capacitor for phase splitting (or value changed with time) resulting in the optimum phase shift no more obtained for desired torque-speed curve.
How about wear and tear in ball gearings, dust collected in the mechanical parts or other mechanical influences to the drive train?
Does "reduction" refer to a sudden decrease in speed or did it happen when you first installed the fan?
Maybe it is designed for 60Hz and you drive it using 50Hz only?
Many ceiling fans commercially available do feature more than one speed, so maybe it is just misconfigured. Check weather you have two switches on it. One is for ON/OFF, the other is done to cycle through various speeds like low/medium/high, restarting from low if you retrigger it at high speed.
If you're talking about something controlled by power electronics, (mis-)configuration is most likely the root cause of wrong speed.
Change in magnetic circuit reluctance(increased), due to rusting with time,should also considerd, in reduction of speed.
Thank you dear professors. Your contribution is highly appreciated.
1. Dr. Biswas
1) For the case which I am considering, all of voltage and frequency are the rated ones, as well as the blade angle is the same designed angle. It seems that the reason is the phase splitting capacitor value change with time, resulting in the optimum phase shift no more obtained for desired torque-speed curve.
2) Any related reference, manual, or web site sharing is highly appreciated.
2. Dr. Schulz
1) There may be a gearings problem.
2) The reduction mentioned refers to a continuous rotation with low speed.
3) When the fan was first installed its speed was normal.
4) The design and operating frequency is 50Hz.
5) The ceiling fan is the normal one regulating switch (with five positions and OFF position).
6) Any related reference, manual, or web site sharing is highly appreciated.
3. Dr. Desai
1) The magnetic circuit reluctance change with time may be the cause of the reduction of speed in my case.
2) Any related reference, manual, or web site sharing is highly appreciated.
- Badges
- Science topic