Help with motor from old grain mill

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tinman1973

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It looks like a single split phase with maybe a start winding as well, Does it have a centrifugal switch on it to disconnect the start winding? On the 2 main windings, one may have a tick wire with high inductance, the other will be a thinner wire with higher resistance and lower inductance, this gives the phase difference to enable rotation of the magnetic field.
You can have a single phase starter, all a starter is, in essence, is a means of controller the supply to a motor and some overload protection.
 

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Baffledron

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Brilliant, we're getting somewhere...thanks.

Yesterday I measured the winding resistance using my general purpose multimeter, it's not an Avo but it is good enough to give a rough idea of the values. Sketch of what I found out as attachment below.

Definitely single phase with split phase starter windings. Probably dual voltage...could that be 230v (main windings in parallel)and the old 2 phase 460v (main windings in series)?

Now emboldened, I connected it all up and powered it up....initially nothing. Then spun the motor by hand and applied power...it worked. Stop then start again, all working fine. Possibly initial reluctance to start was the centrifugal switch sticking?

Stopped and started a few more times... all working, you can hear the centrifugal switch working just after power is applied. Left it running for half an hour, stop then start....all working.

At some point in the future it might be an idea to take the fan and end casing off to inspect the centrifugal switch but the aluminium fan is well stuck (and keyed) to the shaft and will need a puller on it to get it off....but that's for another day.
As a work around, there is a hole (drainage/ventilation?) in the underside of the end aluminium casing, I imagine this void is where the centrifugal switch is. So I used this hole to spray contact cleaner in hoping that it'll get to the centrifugal switch...we'll see!!

Many thanks

Ron Wiring schematic.jpg
 

Baffledron

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Hi,

The mill, well I know very little about it.

It's made by a firm called Dening (Chard in Somerset), it's a roller mill for rolling cereals (eg. porridge oats). You load the grain into the hopper and its squashed between the rollers.

The serial number contains 1965 which makes me think it dates from then.

My research so far has drawn a blank, the firm closed (in the mid '60s?) and left no trace of their roller mills.

The mill itself hasn't been modified, but I think the motor might have been changed at some time. The reason I say this is that the mill has a flat belt drive pulley and the motor has a v-pulley with 3 v-belts running on the flat pulley, a bit unconventional!.
There is an adjustable mount for the motor, this is part of the original casting, so it was made to be driven from an electric motor (as well as from a tractor PTO drive pulley?).
The Newman motor that we've been discussing here has its connection box facing down making it difficult to wire up, I doubt whether this would be part of the original design. Surely they would have chosen a motor format with easier access to the connection box?

That's about it.

Photo below of the mill bolted and strapped to a pallet ready for collection by pallet courier.

Cheers

Ron

Mill on pallet.JPG
 

Geoff1946

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Have you found :- https://www.gracesguide.co.uk/Dening_and_Co


Also, enquiry on a milling forum I belong to produced the following history:

Stephen Bartlett
Started as Wightman and Denning, John Wightman a local farmer bought the forge in 1828 and Started making farm machinery in 1842 Charles Denning joined the partnership in 1867 Wightman retired leaving it as Denning & Co moving to a new premises in Crimchard. Chas son Samuel ran the business adding kitchen stoves and cast iron crosses fir graves.
The family were very prominent in Chard.
Became Denning &Co Ltd in 1937.
WW2 made aircraft parts after the war they lost out on the corned beef war with Argentina going in to liquidation in 1950, their machines can still be seen working in Australia and S Africa
 
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Baffledron

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Thanks Geoff for finding that out, much appreciated.

That's about as much as I'd found out myself.

You would have thought that there would be literature and drawings somewhere...good idea try the local archives!

Many thanks again.

Ron
 

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