Field coil power compression - for Steve Schell - John Sheerin

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Field coil power compression - for Steve Schell

Steve,
I finally got around to looking at some data today relating to power compression in field coils at various field coil voltages. I measured a Rola 12" with something around a 560 ohm coil. Going from 75V to 140V showed a reduction in power compression from around 0.8dB at 75V to 0.2dB at 140V. This was at 16V input to the voice coil (nominally 32 watts). I calculated the expected difference in output due to the efficiency difference (in the more efficient case the voice coil is dissipating less power as heat, so resistance goes up less and thus output should be higher) and also included the different measured DC coil resistances and only came up with 0.16dB, so I'd say there's something else going on. Possibly it's what I mentioned before or possibly it's something else that I'm too tired to think of at the moment.

Oh, and just fwiw, 130V seemed to be saturating the motor structure, and going to 140V didn't change the amount of power compression.

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Topic - Field coil power compression - for Steve Schell - John Sheerin 18:50:37 07/23/07 (3)

RE: Field coil power compression - Steve Schell 20:05:10 07/23/07 (2)

RE: Field coil power compression - John Sheerin 16:37:44 07/25/07 (1)

RE: Field coil power compression - JeffreyJ 17:57:56 07/29/07 (0)

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