Garden supply chainsaw not working

I think that's a somewhat different issue, tho', stateit.

The 'lower voltage' we're are talking about in this case is brought about by the increased resistance of the cable - a resistor is effectively being placed in series with the motor. Ergo there is no way that a heavily-loaded or stalled motor in this case is going to draw more amps than if it were connected directly to a full-voltage mains supply.

Take it to its logical conclusion; let's forget the stalled motor and have a complete short-circuit at the end of that cable instead. How big will the 'bang' be if the cable is (a) 1m long, (b) 100m long and (c) 10,000m long?

Ans (a) BIG! (b) Big! (c) Pfffft.

Now sticking a stalled motor at the end of that 10,000m long cable ain't gonna be pulling more amps than with the 1m lead.

 

Sorry DA.

A stalled or heavily loaded motor will always draw more amps. Undervoltage or normal voltage. Undervoltage exacerbates this in a straight-line graph (heat effects on motor-windings ignored).

Try explaining your theory to my father-in-law who trips the OPD (16A MCB) on his generator frequently when he's cutting oversized logs with his electric chainsaw.

We're going to have to agree to differ on this.

 

No we're not... .

Yes, I know that a stalled/loaded motor draws more amps. That's not in question here.

And perhaps 'undervoltage' as in a drop in the mains supply or something weird, or a gennie that's not regulated properly - I dunno - might cause unexpected reactions.

But, voltage drop due to increased resistance - eg a long cable - is simply not going to draw more amps. It ain't it ain't it ain't...

 

Agreed!

 

Phew - thank you, Sen.

I do understand what you are saying, stateit, but this voltage drop is caused by the loooong cable.