Hi All,
I've read a few places on the web about motors or drivers not working well with "Switching" power supplys.
Why?
Thanks,
Evan R.
Hi All,
I've read a few places on the web about motors or drivers not working well with "Switching" power supplys.
Why?
Thanks,
Evan R.
Hi Evan,
I think that switching refers to the method of rectification of the AC supply to make DC. Somehow, the power supply outputs a series of pulses that simulate a DC current. The waveform is not dead smooth like true DC, but is chopped.
A PWM amplifier runs on this chopped DC, I believe.
If you go for a real DC power supply to feed your amplifiers, you will get around the choppy DC problem.
I believe that the motor needs to possess a certain amount of inductance to smooth over the jaggedness of the "switched power" supply. Motors will typically have a rating in millihenrys or microhenrys that give you a ballpark figure to compare with the specs of the motor load recommended for a given power supply.
Balsaman might know more about this stuff![]()
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
As far as I know Hu is correct. A switching supply often doesn't use a transformer. PC supplies are switching supplies. There are filters and such to smooth the DC tho and to my knowledge a switching supply works fine for steppers and such. Perhaps the performance is not optimal, I am no expert on the subject. I used a PC supply on my first router with great success, as have many others.
Eric
I wish it wouldn't crash.
Switching power supplies rectify the AC line voltage and filter it at about 320VDC (voltage doubler rectifier). This DC voltge supplies a pulse-width regulator that operates at 40 to 100kHz. The high frequency is passed thru a transformer and is rectified back into a DC voltage.
Why do all that? Transformers are much much smaller at high frequencies and the pulse-width "switcher" regulates the output voltage without generating heat the way a linear regulator does.
The result is a small and light power supply, often less than 10% the size of an "iron" power supply (xformer, rectifier, filter cap). If a linear voltage regulator is used with the "iron" supply then the heat generated can be enormous, a problem the "switcher" doesn't have.
Mariss
Thank to everyone.
Now, I understand well enough to move on t the next step of building.
Thanks,
Evan R.