Mystery object - F125 prototype maybe

[HPsauce]

This strange object lurks in an old derelict building not far from where I live.
Does anyone know what it is? I reckon it's Audi's first prototype F125 switch....

[tc4332]

Single phase electric motor starter switch.

[HPsauce]

Thanks Ray, we think the building was once some sort of pumphouse so that makes sense.
Out of interest how did you identify it and how (if you can describe briefly) does it work?

[HPsauce]

So a further challenge, this is the "pump" in the same building...

[tc4332]

Originally Posted by HPsauce

Thanks Ray, we think the building was once some sort of pumphouse so that makes sense.
Out of interest how did you identify it and how (if you can describe briefly) does it work?

Oh dear, that is beyond the realms of my memory.
I'll try.
Large motors could not be just connected and away they would go.

Power was fed to the starter. You then turn the handle clockwise, one click at a time. The switch passed power via those segments to different windings in the motor.
Sorry I can't remember the actual format of the windings but I do know that at start the field windings were in series with the armature, this gave high torque at low speed. As the motor built up speed you turned the switch further and further until the motor was running at maximum in series speed. The next click then put the field windings into parallel with the armature which gave high speed at low torque but it had enough to keep turning. In this position the control was held by an electromagnet.

To stop it you just switched off the supply, the motor slowed and stopped because of the load. At the same time the electromagnet released the switch and under spring tension it returned to the off position.
All my notes and records of these types of things are at the bottom of some sea somewhere with the rest of my kit.

[HPsauce]

Originally Posted by tc4332

Large motors could not be just connected and away they would go.
Power was fed to the starter. You then turn the handle clockwise, one click at a time. The switch passed power via those segments to different windings in the motor.

Cheers Ray, that makes total sense to my scientific mind. It's just that I know little about the detailed design of large electric motors.

[tc4332]

Originally Posted by HPsauce

So a further challenge, this is the "pump" in the same building...

That is probably an air compressor but I know nothing.

[tc4332]

I think that is a single phase motor switch.
With three phase motors it was somewhat similar but the windings were star then delta connected.

[27litres]

Makes sense to me Ray, as that's how the control works on our older train fleet with DC traction motors:
- Shunt (a high amp starting current to get the motor past the friction point (starting current)
- Series (armatures powered in series for maximum torque during low-medium speed acceleration
- Parallel (armatures switched to parallel for med-high speed acceleration)
- Weak Fields (now this is an interesting one - DC motors use permanent magnets. As more power is applied through the armatures, they create a stray magnetic field which acts as a resistance to the propelling field between the armature and permanent magnets. This gives the motor a maximum rpm as the stray magnetic field and the field created by the armature and permanent magnet balance out.
A tricky bit of magnetic manipulation called field weakening (not sure if it's electro magnetic, or some sort of current fiddle) can then be applied which artificially reduces the strength of the stray magnetic field to allow the motor to spin even faster).

[tc4332]

Originally Posted by 27litres

Makes sense to me Ray, as that's how the control works on our older train fleet with DC traction motors:

Hey Marty,
Now you have me interested. I am sort of interested in all things train.
Currently learning all I can about DCC on model railways.

Oh and pipe dreaming!!!!
When the kids move out I'll have a model railway room.