Bad motor

[ljk]

I'm a avid forum watcher, most advice given is really  good.  I have a problem.  I serve as free sewing machine

repairman in a high mountain valley in Colorado.  Last summer I installed a motor and flywheel

on a Bernina.  This was originally converted to a treadle. This family had moved to the valley

built a house and installed solar.  I converted it back to electric.

 

After a few months she called and said the motor burned up.  Any suggestions?   Bernina motors are

very expensive. Is it possible the solar voltage could vary enough to cause a problem.  tx Lynn

[mikesc]

Bernina what..( they made both domestic and industrial )..what was the motor spec..
Solar panels output DC..to get that to AC ( which is , I presume, what the motor you fitted would be running on ) that DC needs to be put through an inverter..If the inverter is faulty* or not giving a stable output*, then a motor could "burn out" due to that..

*You'd need to measure ( with a meter ) the output of the inverter to know..

Motors can also "burn out" because someone forces the machine, real easy to let the magic smoke out, I got a free Singer 20U because the guy who was selling it plugged it in in front of me and the magic smoke came out of the motor ( industrial clutch motor 220v 500w ) ..for him that meant the machine was "scrap" ( he didn't know that you can simply replace the motor on an industrial machine, even though it is obviously separate from the head ) so he asked me if I would be kind enough to take it away, and save him the trip to the dump as his car was to small to fit the machine and the table in..he even offered me money to do so, I smiled and said no to the money, but that of course I'd be willing to take the "scrap" machine off his hands..I had driven 160 kms to look at it ( which he knew )..fitted another motor, now it runs beautifully. :)

Without knowing more details about your machine, the motor, the power supply, no one can really say if it was more likely to be the motor, or the power supply.

Edited December 3, 2017 by mikesc

[LatigoAmigo]

You might see if you can determine what the solar inverter's output looks like, i.e., the sine wave viewed through an oscilloscope. Some inverters don't put out a true sine wave, but rather a modified sine wave (sometimes even a "square" sine wave), and this could be the basis for the problem. I have seen solar installations with optimization filters that had to do with the quality of the inverter output, so you could contact your customer's solar installer to see what they know about this issue.

(Point of clarification: In my former day job I was an electric metering systems technician for our local utility, and have visited thousands of solar installations. I'm now retired.)

[ljk]

Thanks for advice. My concerns are two. I am installing solar.  I currently run 3 commercial embroidery

machines on the power grid.  These machine are run with Newpoint battery backup surge protectors.

Will that give me any protection, my solar installation is being installed by professionals, what d. I tell them.

Secondly my customer is Amish, and the community is rapidly going solar. i worry that some my

buy electronic machine (most are using mechanical) but do want more features rather than just

straight stitcher.      tx Lynn

[mikesc]

AFAIK.."surge protectors" ( you don't give "the spec" of yours )  are unlikely ( have to say that without seeing the circuit diagram of yours..most do not protect against anything other than surges ) to give you any protection against "squareish" sine wave output.

LatigoAmigo put "it" more technically (not very often that one comes across anyone who has  'scopes these days, let alone knows how to "troubleshoot" with one, "my hat is doffed Sir" ) than I might have..But, I think that what you are asking cannot seriously be diagnosed in a forum ( given the "tech level" of your replies )..you really need to be working with ( as in face to face ) a technician with the background and experience of LatigoAmigo..otherwise I can see in your's and your customer's futures, a great deal of "magic smoke" escaping..the cost of which could very rapidly outpace the cost of paying someone like LatigoAmigo who knows what they are doing and what they are looking at , and looking for.
 

Edited December 4, 2017 by mikesc

[LatigoAmigo]

You don't really need to put a scope on your inverter output, because you should be able to get that type of technical information from the company that built the inverter, or possible the company that installs it. Or, very likely, a forum or blog site where solar users discuss such topics. This type of information should be very available these days.

[480volt]

In regards to your Bernina problem, it’s a bit vague to say “they installed solar”. Is this a completely off-grid house, with panels charging a battery bank? I’ve seen such a system struggle with motor loads (table saw, skil saw, etc). If it is off-grid, I’d ask your customer to hook up a big load like a table saw or appliance and meter the voltage output. The more the voltage sags, the more current will be drawn by the load.

In regards to your other solar installation, if you are putting in a system on a building with an existing service from a utility, than you should have no problems. The inverter is typically tied to the panel via a breaker, and feeds the panel in parallel with the service. You won’t see any difference on circuits fed from this panel, as the contribution from the inverter is just supplementing what the utility is providing.