Bacon slicer advice needed

[AllAlloyCup]

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After cleaning the various bits of this dastardly machine and cleaning 
out the switch contacts this bacon slicer starter motor now freely motors... in fact a bit too freely!

Everything seems correct, nothing broken or jammed
But when power is applied to it the motor spins healthily
but the starter dog gear spirals away from the ring gear not towards it!

It’s as if the motors turning the wrong way?

I had assumed the bacon slicer was negative earth ? The car is to be wired
Negative earth. Are there positive earth bacon slicers?

It’s a new battery.

I’ve not had the Bendix apart, just cleaned the gears and commutator

This starter motor came with a pile of bits so don’t know it’s history.

Is it me or is something fishy going on?

The bits match exactly those in Woodward’s big red book.

Any suggestions gratefully welcomed.

Regards

Bill G

[Ian McGowan]

Hi Bill, 
         I would suggest that you are running it with polarity reversed. My Bacon Slicer on a 1929 chummy is negative earth ( I tend to believe that all bacon slicers were intended to run negative earth)  Is that your situation ? Whatever, it would appear that the motor is running in reverse, as it were. Have you possibly connected the actual electric motor the wrong way round?

[AllAlloyCup]

Thanks Ian

Can you reverse the polarity in a similar way to changing
The polarity of a dynamo?

Either that or the new battery casing is wrongly marked?

Regards

Bill G

Ps I have another old 6v battery so will try that to check.

[Ian McGowan]

I have never done it, Bill but I imagine that swapping over which wire is connected to which terminal of the electric motor would reverse the direction of rotation.

[AllAlloyCup]

Hi Ian,

Thanks for your comments.

The trouble is there is only one connection to the motor,
The other is Earth. If I connect the single connection to the negative
Post of the battery, the case would have to be positive...
I’m not sure what this would do other ?

I bought a pile of neg earth LEDs so that would be a complication.

I’ll look up reversing polarity of dynamos but not sure if
Such a procedure can be applied to starter motors.

Regards

Bill G

[Parazine]

I have never done it, Bill but I imagine that swapping over which wire is connected to which terminal of the electric motor would reverse the direction of rotation.

Only on a motor that has its field supplied from a permanent magnet.

In a starter motor, the magnetic field is produced from an electromagnet (i.e. the field windings). Thus the field is reversed as well as the current flow in the armature when the supply is reversed and the motor always revolves in the same direction - as long as the field connections are not altered.

Did any of the internal connections get remade?

Is it possible the motor (as opposed to the whole assembly) is from another type of vehicle altogether?

[AllAlloyCup]

As far as I know the bacon slicer motor is unique to Austin 7’s.

I did not disassemble the motor part of the bacon slicer.

More investigation needed .

Regards

Bill G

[AllAlloyCup]

Still bemused by this motor!!

I changed the battery connections
Round and used the negative post of the battery as the main feed
To the motor, using the positive as the Earth.

But the motor ran in the same direction!
With the starter dog returning to the Bendix rather than heading to the ring gear????

I’m completely flummoxed!  

Perhaps I should sleep on it!

Regards

Bill G

[Ian Williams]

To reverse you need to alter the internal field winding connections or the armature connections, by reversing the external connections you have altered both, net result no change in direction.

[Parazine]

But the motor ran in the same direction!

As I said earlier...…(q.v.)

However....

It's just possible that the motor itself (just the motor, not the whole aluminium casting etc) was used on something else and you've ended up with one of those.

Or, someone else has (in the deep past) been inside and misconnected things.

Or, someone has substituted an armature or field coil, wound the wrong way from another application or has had one rewound incorrectly. Remember, 1 out of 2 will result in incorrect rotation!

The other thing to check maybe is the alignment/connection of the brushes. If the connections could be misplaced here to reverse the armature current, that would explain the symptom.....