jpsmith123
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Anyone have experience with Mastech power supplies?
I'm contemplating getting one of these Mastech 20 amp power supplies:
http://www.radios4you.com/mastech-hy3020E.html
It looks to me like it would be a good general purpose supply for small scale electrolysis, electroplating, etc.
I'm wondering, does anyone have one of these or know anything about their performance?
Regards,
Joe
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ordenblitz
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I have the 2020E and so far it works fine. Only used a few times though for anodizing some small parts. Holds settings well.
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jpsmith123
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Thanks for the info, Ordenblitz. I didn't see that model (20 volts max output, I assume). Maybe they don't make it anymore?
Regards,
Joe
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hodges
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Depends on what you are using it for. I have a Mastech HY3005D power supply which I have had for about 1 1/2 years. I thought the constant current
operation would be useful for electrochemistry, but the constant current is maintained by several relays (vs. continuous operation) and these relays
chatter constantly when I (for example) try to electrolyze molten sodium hydroxide. When I use the power supply for electronic circuits, I find it
produces a lot more hum than similar power supplies. Also, the built-in voltage and current monitoring becomes useless if you have the slightest
amount of RF energy nearby (such as when operating a transmitter). Both the voltage and current meters are illuminated with a green light of some
type. I noticed recently that the green light for the voltage meter has gone out. And I probably have used the power supply less than 100 hours.
Maybe I got a lemon, or maybe the power supply is just not useful for the types of things I'm trying to do.
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jpsmith123
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Thanks for that information, Hodges.
For various reasons, I'm now having some second thoughts about buying one; the lack of robustness you imply being one of them.
In any case, it's hard to believe that anyone would use electromechanical relays anywhere in a modern power supply, especially in a voltage or current
control loop.
Is the HY3005D a linear or switchmode type supply?
I know from experience that some switching supplies can "motorboat" (I think that's the term) under certain load conditions, particularly under light
loading, where the duty cycle cannot go low enough and switching becomes discontinuous; i.e., it starts skipping cycles, sometimes causing an audible
tone.
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hodges
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I'm not positive, but because of its heavy weight I doubt it is switchmode. The relays apparently select among voltage "ranges". If the voltage
stays within a given range, the relays do not operate except once initially. But if you set a constant current and the conduction is varying (such as
in a non-aqueus electrolysis) the each large voltage variation causes the relay to chatter.
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