Re: Newbie (ignorant) tech question

Hello all,

thank you for all your technical (and whimsical!) responses. To answer a
few questions posed:

This motor runs directly off of the 28 VAC lugs from a transformer inside
the game, and would run continuously while the game is powered up.
Originally when this pinball was operated on location this motor drove a
spinning wheel in the upper box (where the digital scores are); this
spinning wheel would be considered an "attract" feature, in order to lure
more players and hence earn money. In the home setting this is unnecessary,
in my opinion. Furthermore, I think it's a neat effect to have the wheel
start spinning once you initiate a new game.

There is a signal in the game that I could apply to the base of a transistor
controlling the motor; because it is an AC motor I think I would have to use
a relay to control the AC. This would achieve the effect I am looking for.
As a matter of fact (after reviewing the schematics) there are similar
applications for different functions in this particular game I am talking
about, that use a transistor to control relays.

I do have a question though about the particular signal I was referring to
above. This signal emanates from a 74175 TTL chip, and drives a Darlington
transistor, which in turn permits voltage/current to a small relay solenoid.
What I would be doing is essentially splitting that signal to a SECOND,
identical Darlington permitting current to an identical relay solenoid.
Will that signal from the 74175 have enough "oomph" to drive the two
Darlingtons, whose part number is MPSU45? MPSU45 crosses to an ECG272,
according to my ECG cross reference book.

Thank you for reading!

Regards,
Dan


"Dan Beck" <biscuitbecks@*nospam*cableone.net> wrote in message
news:12pt4sgkas5iff2@xxxxxxxxxxxxxxxxxxxxx
Hello all,

I have a constant duty AC (28 VAC) motor that runs in one of my pinball
machines. I wish to control power to the motor such that it only runs
during gameplay. There are "recipe" circuits that do this for DC motors
that do the same thing, in pinball machines. The heart of this "recipe"
circuit is a TIP125 transistor. Will this transistor work in an AC
voltage circuit?, Or, is control of AC motors more complicated than I am
anticipating?

Thank you for any and all responses!

Regards,
Dan



.

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