Hi Tim,
First, I forgot to mention that we ran each OD an hour before measuring the oil
temperature.
You're sort of right on the solenoids. However, the A type has two coils. The
pull-in coil draws between 15 and 20 amperes but is switched out of the circuit
by the plunger bottoming. If it is not switched out, the ~200 watts will
destroy the coil very quickly. The holding coil, (the second coil) draws a
little less than 1 ampere but that produces sufficient magnetic force to hold
the plunger in, once it is operated. (1 ampere at 12 volts produces 12 watts)
Since the pull-in coil is in the circuit for less than a second, it contributes
essentially nothing to the solenoid temperature or average power. The high
current required of the pull-in coil does however necessitate the relay.
The J Type solenoid uses a single coil. The pull in requirements are better
defined since there are no adjustments; the valve is an integral part of the
solenoid. Apparently they were able to make just one higher current coil do the
pull-in job and have a low enough dissipation to also be used to hold the valve
operated and not burn itself up when powered continuously. The J type solenoid
on our unit drew 1.75 amperes after it was hot, hence the 21 watts. The ~ 2
amperes can be handled by the OD and gearbox switches directly.
Nelson
----- Original Message -----
From: "Timothy Holbrook" <tjh173@yahoo.com>
To: <6pack@autox.team.net>
Sent: Tuesday, July 31, 2001 1:04 PM
Subject: Re: OD bench temperature measurements
> Interesting data, but I'm a little confused on one point. I thought
> that the J type solenoid consumed LESS power than an A type. Isn't
> that why the A type requires a relay in it's circuits, and the J type
> doesn't? The A type takes more current, which a switch cannot handle,
> and thus a relay is required. The J type takes less current to
> operate, and therefore needs no relay. Therefore, since watts = volts
> x amps, and voltage is constant (around 12-14 volts produced by
> alternator), the higher current A type solenoid should consume more
> watts. Right? Am I missing something here?
|