Surges & Spikes produced by AC motors
Surges & Spikes produced by AC motors
(OP)
I cannot seem to find any information on the effects of hooking up a compressor or other AC motor to sensitive electronic equipment. I know the motor produces spikes and surges and is destroying switching power supplies in our products. Does anyone know if there are papers or information on the effects of these motors?





RE: Surges & Spikes produced by AC motors
If it is a single-phase motor with capacitor start, you may see a transient when cap is switched out.
If it is a "universal" motor with or without SCR speed control, then it will create a lot of hash on your ac input.
But none of the above probably creates as much electrical noise as a switching power supply. I wouldn't blame the motor too soon. You could try some surge suppression on the input to the power supplies.
RE: Surges & Spikes produced by AC motors
RE: Surges & Spikes produced by AC motors
RE: Surges & Spikes produced by AC motors
RE: Surges & Spikes produced by AC motors
#1 this motor is served from the same ac source as your electronics
OR
#2 - this motor is powered from the output of your electonics
In any case there wil be some inductive voltage spike when the motor is switched off. Also dependent on exactly what kind of device is used to switch the motor off.
RE: Surges & Spikes produced by AC motors
RE: Surges & Spikes produced by AC motors
Does this one from this particular supplier always fail? Is it the only one to have failed? How many have failed? Besides my point above, I do not see any correlation to the compressor and the switching power supply. Is it the compressor or switching power supply distributor that is the only one having problems? If it is a certain switching power supply then change to one that works and don't buy from the other again because your getting junk. Check into any IEC tests that have been done on the power supplies and/or check for CE marking on the device.
RE: Surges & Spikes produced by AC motors
Chapter 1 is on line at: http://standards.ieee.org/colorbooks/sampler/Emeraldbook.pdf
RE: Surges & Spikes produced by AC motors
1. Isolation transformers
2. Power line conditioners
3. DC power supply with an inverter for the sensitive electronics.
4. Etc.
RE: Surges & Spikes produced by AC motors
The alternative is to install the surge suppression and specify which compressors are compatable with your system.
RE: Surges & Spikes produced by AC motors
RE: Surges & Spikes produced by AC motors
Air compressors tend to turn on and off quite frequently and the power quality during starting is extremely poor until the centrifugal switch on the motor takes out the caps. The problems are very breif, but the comopressor cycles very rapidly. If you dont kow, look for a "bump" on the side of the compressor motor. That is a tell tale sign of a capacitor start. The only other type of 1 phase motor would be a "split phase" starting version, no longer commonly used in machinery of this type. Some small comnpressors are using Universal motors (the type used on your power drill for instance) even though they are not using variable speed capability, but they are typically limited to fractional HP.
Actually, in reviewing you original post I see that this is a $50 compressor, so that may in deed be the case. A universal motor usesa rectifier and brushes going to DC windings, very poor power quality and very likely to do damage to your PS. Invest in a line conditioner.
That which does not kill me, makes me stronger... and pissed off!
RE: Surges & Spikes produced by AC motors
RE: Surges & Spikes produced by AC motors
You mention "Ferroresonent are good for this application, small, inexpensive and reliable". I have never heard of this type of protection device. Can you give me some input on where I can get specs on this? I currently have several devices on order to check their supression capability on the AC input.
As for some more background information, the predecessor to this product has been in existance for approximately 35 years and had a linear regulator providing power to the remote motor. A problem it experienced was intermittent (every couple of years) destuction of the regulator. I believe this has been solved with the new product by adding protection circuitry to the output of the switching power supply.
Thank you for your help.
RE: Surges & Spikes produced by AC motors
Check out the CVS or MCR Series products under Power Protection and Conditioning.
That said, Sola lost their patent protection several years ago and there are now several other manufacturers on the market. Do a Google search on "ferroresonant line conditioner" (carefull, I had spelled it wrong in the first post) or "constant voltage transformers". Just be aware that not all power conditioners are ferro's, and some types of alternate technologies will be susceptable to the same problems as your power supply! Also remember that you only need the power conditioner in front of the power supply, not the compressor!
"If it were not for electricity, we'd all be watching TV in the dark!" ...George Goebell.