Search found 45 matches

by Bygar
Wed Nov 13, 2013 3:48 pm
Forum: General Discussion
Topic: Motor Speed Controller
Replies: 4
Views: 1928

Re: Motor Speed Controller

You can NOT vary the speed many AC motors with voltage change! One exception is universal wound motors. Poly phase and most single phase Ac motors require the frequency to changed. Bodine a company which also makes motors can supply 3phase controllers for various sizes of motors. Variable speed driv...
by Bygar
Thu Aug 16, 2012 5:25 pm
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

If you really need variable speed AC drive Single Phase. Here's one although for 230 Volt.
It is 0.75HP,3.5A,230V,1Ph:
Model No. 5WJK1
Grainger Industrial Supply. I believe it Covers 10Hz to 400Hz and has acceleration and? deceleration
timer/s.

I stumbled upon this one. It is close to your spec.
by Bygar
Thu Apr 12, 2012 7:39 pm
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

Did you ever solve the problem. I spotted an AC drive in packages from 1/2 KW to 18 1/2 KW single phase drives at120 Volt. And others for 3 phase for higher power. The brand was "Vacon" They may or may not be variable speed / frequency. The name Kaman was or is the North American distributor. Good L...
by Bygar
Sun Mar 04, 2012 2:25 pm
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

We never asked what type of winding is the motor? True AC motors only can vary the RPM by varying the frequency. The universal motor will vary with voltage change and will run on DC as well. A good Dc power supply tracking positive and negative could be adapted to power an AC motor. You would need t...
by Bygar
Mon Feb 20, 2012 2:36 pm
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

Another way might be to use a sine wave oscillator driving an audio amplifier. You get to keep a sine wave drive. You will need a fairly powerful amp. At a guess about 400 Watts. And a suitable transformer on its output. Careful of the top frequency (speed). Yes some small motors do turn some very h...
by Bygar
Tue Feb 14, 2012 8:37 am
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

You may be able to hack a DC to AC converter.
Using a variable frequency i.e. 555 timer, driving an audio power amp.
with an output transformer to increase the voltage.
Since you are only driving a fractional HP motor.
by Bygar
Mon Feb 13, 2012 11:11 pm
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

To vary the speed of an AC motor Vary the frequency not the voltage.
Voltage will change torque if varied.
Other than Brushless DC motors.
DC motors do vary speed with variable voltage.
If the normal motor RPM is 1750 (1800).
Anything above 2600 RPM would be overspeed.
And could be hazardous.
by Bygar
Sun Feb 12, 2012 9:26 am
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

I suggest a small D.C. motor of sufficient H.P. turning a small generator. Since the power required seems to be about 1/3 H.P. Use a suitable D.C. motor and an automobile alternator and a suitable transformer to get the voltage. Automobile starter motor might do. And use only 1 phase of alternator. ...
by Bygar
Sun Jan 29, 2012 10:18 am
Forum: General Discussion
Topic: PC board coatings
Replies: 12
Views: 2681

Re: PC board coatings

Here is my two cents worth.
Conformal coatings are usually:
Epoxy based,
Urethane based.
Epoxy can be be dissolved by paint remover, none wax version is preferred.
Will probably affect many components.
Urethane will respond to methyl ethyl keytone, MEK.
BYGAR.
by Bygar
Sat Jan 14, 2012 2:41 pm
Forum: General Discussion
Topic: Tiny 2-Way Beeper Needed
Replies: 6
Views: 2146

Re: Tiny 2-Way Beeper Needed

Try Visitect Inc. They have or had Keychain transmitters and moderately small receivers.
Receivers were available as kit transmitters were not.
Email: [email protected]
If still in business.
by Bygar
Sat Dec 31, 2011 5:19 am
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

It is just a matter size. What power is required?
A small DC motor and small AC generator would work.
Of course some losses will occur due to efficiency.
What power is required?
by Bygar
Sat Dec 10, 2011 6:22 pm
Forum: General Discussion
Topic: AC Motor Drive
Replies: 25
Views: 7420

Re: AC Motor Drive

You could use a small motor/generator set, depending on your gearing system you can get different frequencies out. Caution! About 80 hertz should be the upper frequency limit otherwise you could have over speed problems. Hope this gives you some ideas. My experience was with somewhat higher power va...
by Bygar
Thu Nov 03, 2011 9:11 pm
Forum: General Discussion
Topic: Multi layer coil design
Replies: 14
Views: 2897

Re: Multi layer coil design

An easy way to measure inductance is a series circuit consisting of; An oscillator of known frequency A Potentiometer and possibly a selection of fixed resistors A means to measure AC voltages at the frequency of the oscillator The circuit is simple the unknown inductor is wired in series with the p...
by Bygar
Tue Sep 13, 2011 11:41 am
Forum: General Discussion
Topic: old copies of EEM
Replies: 6
Views: 2527

Re: old copies of EEM

If you still want the commodity codes they appear to be the same as the product codes used in the earlier editions. If Lenp's edition lists (2003) are commodity codes mine 1987/88 lists the same as product codes. Sorry just a terminology change. If you still want these codes let me know and I'll try...
by Bygar
Sat Sep 03, 2011 11:40 am
Forum: General Discussion
Topic: A Little Transistor History?
Replies: 15
Views: 2829

Re: A Little Transistor History?

Your 2N168A is listed in the 2nd edition GE transistor manual.
It is a NPN rate grown germanium transistor, designed for mixer/oscillator,
IF amplifier applications.
Vcbo max. 15 Volts.
I Collector max. 20 mA.
Listed in a GE publication May 1, 1956.
I still have some old data books.