Transformer as pickup

[terry5732]

I just ran some trials of using a transformer in conjunction with pulse motor as a generator.
It appears as though the magnets of the rotor will induce voltage in transformer, but the back EMF follows the least resistive path and stays in trafo!
Because the flux of the rotor affects the outside of trafo as well as core , it doesn't induce strongly.
But I could detect NO drag to rotor, so number of pickups only limited by space around rotor.
Eddy current drag is a problem with using many types of trafos - I will be looking for more of the flyback types with ferrite cores.
I may also try to make ones with smaller outsides to see if it induces better while still not dragging.

[saad]

this is not a reply
i want to know if an induction coil can be used as a transformer
if it can be done some one please contact me immediately
with details
number of wire turns
wire gauge etc

[terry5732]

An induction coil is really just half of a transformer. By overwinding another coil on top you have a transformer. The number of turns and gauge depend on what you want for volts and power. There are many good websites that will give you formulas. Just google"transformer winding". However you will need to know what your existing wraps are, and that can be difficult to ascertain short of unwinding and counting


I tried with different coil today - a rewound CRT flyback -and couldnt induce more than a trickle:(
May yet try other configurations.

[hartiberlin]

I just ran some trials of using a transformer in conjunction with pulse motor as a generator.
It appears as though the magnets of the rotor will induce voltage in transformer, but the back EMF follows the least resistive path and stays in trafo!
Because the flux of the rotor affects the outside of trafo as well as core , it doesn't induce strongly.
But I could detect NO drag to rotor, so number of pickups only limited by space around rotor.
Eddy current drag is a problem with using many types of trafos - I will be looking for more of the flyback types with ferrite cores.
I may also try to make ones with smaller outsides to see if it induces better while still not dragging.

Terry,
how didyou measure,
that no drag was applied tothe rotor ?
Can you post a picture of your setup  ?

Thanks.

Regards, Stefan.

[terry5732]

I haven't made a good device for measuring RPMs, I prolly should. I used an auto timing light with a pulse generator to "freeze" the rotor and when a load was applied it remained frozen(didn't change speed). Just a simple pulse motor made from a roller skate wheel. Similar to SGM.