Magnum Inverters and High Inductive loads

DMJ72

Hey all,

Its time to upgrade my Samlex 1500watt inverter. In a recent discussion with one of our leading Renewable Energy providers, I was told to avoid the Magnum Inverter-chargers in situations that use HIGH inductive loads. Reason : issues with the transfer relay's reliability. I trust their opinions, and they are the kind of family run business that puts good advice to customers over profit/making a quick sale. But I have not heard of this before, so I decided to do some research...



I found these two links :

http://mvvikingstar.blogspot.com/2013/02/compatibility-issue-between-ms2000.html

and

https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/msg05095.html ->>

"I have observed that the MS4448 waveform quality degenerates quite rapidly with imbalanced loading of one or the other of the 120 volt output legs. I can't give a quantitative (% distortion/amps) number to it, but I would classify it as severe. I first noticed it when doing some test measurements in the shop, and found large discrepancies between various current metering devices I was using, as some of the meters were not measuring RMS, and the distortion was throwing them way off. And when using 120 volt motors, even though their surge may be well within specified load limits, count on things not going well."

Has anyone here experienced/heard of this?

SolInvictus

Re: Magnum Inverters and High Inductive loads

DMJ72 wrote: »

... avoid the Magnum Inverter-chargers in situations that use HIGH inductive loads. Reason : issues with the transfer relay's reliability.

This statement does not make sense to me because the transfer relay switches the unit between its two operating modes: an inverter and a battery charger. I do not see how a problem with high inductive loads would be related to the relay. Does the unit mistakenly switch from inverter to battery charger when starting a high powered motor?

DMJ72

Re: Magnum Inverters and High Inductive loads

SolInvictus wrote: »

This statement does not make sense to me because the transfer relay switches the unit between its two operating modes: an inverter and a battery charger. I do not see how a problem with high inductive loads would be related to the relay. Does the unit mistakenly switch from inverter to battery charger when starting a high powered motor?

I am not sure what the post-mortems were, just that the relay went south in a few units that were used in such scenarios. I have a feeling it may also have to do with people using the U.S.A. PAE series here where we have a 50Hz grid. The lower limit of AC qualification is 50Hz, sometimes the grid frequency drops to 49.9 or 49.8 Hz. That may contribute to the relay being overworked?

mike95490

Re: Magnum Inverters and High Inductive loads

DMJ72 wrote: »

...... The lower limit of AC qualification is 50Hz, sometimes the grid frequency drops to 49.9 or 49.8 Hz. That may contribute to the relay being overworked?

Relays are supposed to be able to handle tens of thousands of operating cycles. going bad in a couple years, with fused contacts, means some spec was overlooked.