Spellman noise

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Nicker
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Spellman noise

Post by Nicker » Thu Jan 20, 2011 11:55 pm

Testing the power supply from 0--62kv it makes some odd noise from 45-54 -kv. Like a lose serpentine belt. What could this mean?

http://www.youtube.com/watch?v=wSwtp0qHkjg

Dustin
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Re: Spellman noise

Post by Dustin » Fri Jan 21, 2011 6:03 am

Its probably just acoustics from the windings vibrating in the fields in a specific load range.
Its fairly common for switchmodes to do this. (annoyingly)

David Geer
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Re: Spellman noise

Post by David Geer » Fri Jan 21, 2011 7:06 am

I agree with Steven. I've experienced this in the past with other pieces of equipment and it's just harmonics in the vibrations AND yes, it's very annoying if you work in that range continuously but it's harmless.
- David Geer

Nicker
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Re: Spellman noise

Post by Nicker » Fri Jan 21, 2011 3:22 pm

Thanks for the peace of mind.

Cliff S
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Re: Spellman noise

Post by Cliff S » Wed Jan 26, 2011 6:48 pm

Nick,
Sorry to spoil your peace of mind...but this is not normal. Sounds like an instability in the voltage regulation loop. Unit may have been damaged at some point in its life.
Often the point(s) of instability will change as a function of line and/or load. Under some small load current, it may disappear. Or, it may get worse. You would probably notice this instability if you were monitoring the HV output on a scope, via a divider or blocking capacitor. (Don't try this unless you are experienced in HV measurement techniques!!!). You can also try to look at the kV test point on the rear panel. It may have adequate BW to see the instability. (Pin 6 on the terminal block or connector). Check our website out for the operation manual of the SL300W series.

http://www.spellmanhv.com/en/Technical- ... SLMAN.ashx

Best Regards,
Cliff Scapellati
Executive Vice President of Engineering
Spellman High Voltage Electronics
631-630-3110

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