Testing The Well being Of Motor Windings – Is It Being Accomplished On The Fly In Present EVs?

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In March 2014 my good friend Steen Carlsen who’s an influence electronics engineer wrote a paper wherein he wished to provoke the event of a conveyable and a stationary “Winding Tester” for electrical machines (motors, turbines, and transformers). He had no data of such a tool being out there, and thought it could be an amazing profit to shift from a “preemptive upkeep” protocol to a “change when wanted” protocol for electrical machines in any business worldwide.

He nonetheless has no data of such a tool being out there, and he believes that present winding testers — just like the ALL-TEST Professional 7 — doesn’t apply the identical idea.

When Steen informed me in regards to the paper lately — I imagine we have been discussing electrical transportation — I didn’t even know there was such a factor as put on and tear of the insulation of copper windings in {an electrical} machine. It turns on the market really is, as a consequence of electromagnetic forces that act on the bodily wires in such a method they transfer/vibrate ever so barely — inflicting the insulation of adjoining wires to rub in opposition to one another to the purpose the place the insulation grind via or cracks leading to brief circuits. This, in flip leads to warmth and energy loss, spiralling uncontrolled till full failure.

I questioned if the treatment in opposition to this — that Steen had now defined to me — may already be in use in the actual world? That is one thing that’s close to not possible to analysis, as a result of motors simply work, till they don’t. A producer of a product can state an anticipated lifespan of a product, e.g. one million miles for an electrical motor in a automobile. However it’ll typically be guesswork, because the producer can not know the torque sample, to which the motor might be uncovered over time. Nonetheless, may they’ve this sort of monitoring of motor well being carried out — maybe undetected by specialists like Sandy Munro? Not an opportunity, proper?

With permission from Steen Carlsen I’ve enclosed his paper right here and I might urge any tech savvy electrical machine nerds on the market to assist work out if this idea is in precise use. My good friend Steen and I are simply curious, and our hope is that you simply — having perhaps now heard about this idea for the primary time ever — might be curious too.

Here’s a barely edited excerpt of the paper because it was written nearly 10 years in the past:

Till this second in historical past it has not been attainable to observe the event of damage within the insulation in electrical machines i.e. motors, turbines and transformers. Not till deteriorated insulation has brought on partial discharges, and thereby indicated an imminent deadly winding failure, has the wear and tear hitherto been detectable. This paper presents a brand new means to observe the event of the deterioration within the wire insulation in electrical machines and thus present peace of thoughts for his or her homeowners.

The idea is predicated on monitoring the shift within the resonance frequencies of the resonance circuits constituted by the inherent inductance of the winding flip(s) and the (rising) capacitance attributable to the declining thickness of the layer of the lacquer insulation within the areas the place the insulation will get worn.

The shift in resonance frequencies will be detected by measuring the machines winding impedances Z(s) as a operate of the frequency.

Most electricians would diagnose {an electrical} machine by evaluating the currents in its three phases or by utilizing a comparative measurement of variations within the resistances of the three windings. However not till a deadly breakthrough within the wire insulation has occurred will one be capable of detect any important change within the resistances of the three windings nor any important change within the section currents. Thus, these strategies can’t be used to foretell the remaining lifetime till simply earlier than the machine is about to perish.

The next pages current a brand new idea for detecting put on within the winding insulation in electrical machines. This technique additionally permits establishing which of the section windings is about to perish.

Put on in electrical machines results in lowered thickness of the lacquer insulation of the wires, which in flip, causes a change within the capacitance between adjoining (wire-) turns within the machine.

The detection of the modifications within the capacitance will be finished both within the frequency area i.e. the impedance Z(s), and/or the time area i.e. via the change within the propagation delay via of the windings.

All through the operational lifetime of the machine and up-to-the-minute of failure, the bodily configuration, therefore the variety of turns and thus the inductance between any such areas will stay unaffected by the wear and tear and tear of the machine. Therefore, so long as the cores of the 2 adjoining turns within the winding haven’t but shorted collectively, the inductance between the 2 areas stays unaffected by the wear and tear. The capacitance, nonetheless, will improve by the wear and tear of the insulation. Therefore, because the insulation will get worn, the resonance frequency — related to capacitance and the inductance between the 2 worn areas — will drop.

Be aware that already throughout the manufacturing of the machine, because the wire stress is utilized by the winding machine, and the wire is drawn right down to relaxation on prime of the underlying layers, the deterioration of the wire insulation might be began.

You learn that accurately. It is a non-invasive method of measuring the well being of {an electrical} machine, whereas in operation! Had it not been for Steens Carlsen’s lifelong merrit, I might have thought this was not possible.

The letter is a 17 web page lengthy doc of appreciable technical element of how this manner of measuring put on in electrical machines might be carried out. It’s method over my capability of understanding intimately, however I get the details.

To summarize just a few questions that come to thoughts:

• Is this method being utilized in the actual world in the present day?
• Is this sort of method eligible to be patented, or is it already? (Based on Steen Carlsen one thing like this was patented a few years in the past, however the patens was not uphold, so this concept could be free to make use of by now?)
• Does this apply to hairpin motors too?

Contemplating the acceleration within the electrical car disruption, I discover this sort of factor exceedingly related. Give it some thought, {most electrical} machines has traditionally been chugging alongside in largely static, confined, and secure environments, however now hundreds of thousands of EVs are getting out within the wild, in a comparable a lot harsher atmosphere of vibration, excessive temperatures, and violently shifting energy hundreds (acceleration, recuperation).

I might encourage you to remark beneath when you have any data of this novel method of monitoring electrical machines. Perhaps it’s not even information? And even attainable? However whether it is, wouldn’t or not it’s cool if somebody used this to make electrical machines much more dependable?