[Nut-upsuser] problem with output voltage on a mustek ups

Arjen de Korte nut+users at de-korte.org
Thu Mar 6 11:28:08 UTC 2008

> My problem is that sometimes the UPS is running OK, but when the
> message "UPS is trimming incoming voltage" appears on knutclient (i.e.
> OL TRIM in nut), I have something like
> Input Voltage
> 	241.1
> Output Voltage
> 	202.0
> 	nominal 220.0 ???
> This output voltage is too low! I  think power spikes may be better
> than using this voltage.

I don't think so. Unless the input voltage is exceptionally low (but then
the UPS would switch to battery), the power supply will not be hurt by it.
An input voltage that is too high, will hurt it, so I wouldn't worry about

> I don't know if the problem is the UPS or from communication with it.
> Can you please help me checking  this? I have search on the web and on
> the nut mailing-lists, but I didn't found anything.

NUT has no way to control is the UPS is using BOOST/TRIM, this is
something that the UPS decides all by itself. So there is nothing we can
do about it, complain to Mustek if you feel this is wrong.

Best regards, Arjen
Eindhoven - The Netherlands
Key fingerprint - 66 4E 03 2C 9D B5 CB 9B  7A FE 7E C1 EE 88 BC 57

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