--Looking for a variable frequency drive, A/C but I don't need a
huge one. The application is to drive something other than a huge motor (I'm
fooling around with frequency-controlled color change of electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got a
recommendation?

--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
www.nmpproducts.com
---Decks a-wash in a sea of words---

On Sep 3, 11:23 am, steamer wrote:
--Looking for a variable frequency drive, ..... I'm
fooling around with frequency-controlled color change of electroluminescent
wire)
"Steamboat Ed" Haas

You -might- be able to drive it with an audio oscillator and amplifier
feeding into the speaker side of a 70V audio line transformer. Don't
use a power transformer, it won't handle kilohertz frequencies.

jw

On 03 Sep 2007 15:23:02 GMT, steamer wrote:
huge one. The application is to drive something other than a huge motor (I'm
fooling around with frequency-controlled color change of electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got a
recommendation?

I doubt that motor drives will work for you, nowever, I have several
drives, rated for single phase and for three phase, 1/2 HP, and
up. They are for sale.

i

instead of looking for motor drives, look at the specs for the 555 chip -
this will meet your needs

"steamer" wrote in message
...
--Looking for a variable frequency drive, A/C but I don't need a
huge one. The application is to drive something other than a huge motor
(I'm
fooling around with frequency-controlled color change of
electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got
a
recommendation?

--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
www.nmpproducts.com
---Decks a-wash in a sea of words---



--
Posted via a free Usenet account from http://www.teranews.com

According to steamer :
--Looking for a variable frequency drive, A/C but I don't need a
huge one. The application is to drive something other than a huge motor (I'm
fooling around with frequency-controlled color change of electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got a
recommendation?

Well ... Mitsubishi has a tiny one (single hand holdable) which
will run from 120 VAC single phase, and produce 240 VAC three phase to
drive a 1/8 HP motor.

But part of the question is -- what range of frequencies do you
need? I got this one hoping to use it to drive some aircraft
gyrocompass and artificial horizon devices -- but discovered that unlike
the larger ones, which would go up beyond 400 Hz, this one would only go
to something like 120 Hz. I'm still looking for a three-phase motor of
the 1/8 to 1/4 HP range to drive from it, to hang on the Taig lathe.

Back when I got mine, it was from eBay at a price of around
$45.00 IIRC.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

apparently my posts aren't making it through Teranews again - anyway,
I had attempted to say:

instead of looking for motor drives, look at the specs for the 555
chip -
this will meet your needs

as I recall, EL panels use almost no current so you may well find that
the 555 alone can do the trick. and the chip is cheap, 5 cents to 25
cents in single quantity the last time I looked

bill



On Sep 3, 8:23 am, steamer wrote:
--Looking for a variable frequency drive, A/C but I don't need a
huge one. The application is to drive something other than a huge motor (I'm
fooling around with frequency-controlled color change of electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got a
recommendation?

--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
www.nmpproducts.com
---Decks a-wash in a sea of words---

On Sep 4, 1:13 am, wrote:

as I recall, EL panels use almost no current so you may well find that
the 555 alone can do the trick. and the chip is cheap, 5 cents to 25
cents in single quantity the last time I looked
bill

http://www.elwire.com/faq/faq.html

The oscillator is easy but look at the voltage required. I'd try a
70.7V PA amp or fake it with the circuit I mentioned above.

jw

--Thanks; sounds like a 555 is the simplest solution. I'll take a
look at the schematics if I need more driving power.

--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
www.nmpproducts.com
---Decks a-wash in a sea of words---

you can run a 555 at about 30 V (off the top of my head), you can drive an
old audio transformer backwards, to get higher voltage, or use a single HV
low current transistor to switch higher voltage (I did this with 600V on the
deflection plates of an oscilloscope tube years ago)



"Jim Wilkins" wrote in message
oups.com...
On Sep 4, 1:13 am, wrote:

as I recall, EL panels use almost no current so you may well find that
the 555 alone can do the trick. and the chip is cheap, 5 cents to 25
cents in single quantity the last time I looked
bill

http://www.elwire.com/faq/faq.html

The oscillator is easy but look at the voltage required. I'd try a
70.7V PA amp or fake it with the circuit I mentioned above.

jw




--
Posted via a free Usenet account from http://www.teranews.com

On Sep 3, 8:23 am, steamer wrote:
--Looking for a variable frequency drive, A/C but I don't need a
huge one. The application is to drive something other than a huge motor (I'm
fooling around with frequency-controlled color change of electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got a
recommendation?

--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
www.nmpproducts.com
---Decks a-wash in a sea of words---

If you are just hacking around and don't need to build this as
finished box. Then I think the easiest way to get there is to:
1) Get this or other software like it --- http://new.epanorama.net/software-pu.php?id=24
It's an audio oscillator program for your PC that outputs sine waves
from the audio output of your sound card. I have not tried this
program but only did a search for "oscillator program" on Google. I'm
sure there are plenty of these out there however.
2) hook the audio out of your PC to a stereo or any audio amp (all you
need is one channel - everyone's got an old stereo lying around -
right?)
3) Hook an old transformer (like 110V to 12V or 6V) up to the speaker
output of the amplifier. Connect the 12V side to the amp the and 110V
side will be your output. Note that the frequency response of any old
ac transformer will be fine for this purpose. It's not golden ears
audio. I have used these transformers for real audio in a pinch (old
TV repair days) and they work fine at much higher frequencies than
people realize.

You can dial the frequency on you PC and adjust the amplitude with the
amplifier's volume knob. Note that you can get some pretty high
voltages this way. At full amp volume, you might get 40 VAC at the
speaker outs, then after 12x on the backwards transformer, that can be
500V. The EL wire might need only a 100V or so, so start with the
volume down. it would also be a good to affix a multimeter to the
output so you can constantly monitor the output, but you might need a
better than junker meter to read the correct voltage at higher
frequencies than 60Hz.

This might be a bit a involved, but if you've got this stuff around.
It will be free and very adjustable.

If you are serious, try a real power amp,. These are $105 each, maybe
a cheaper lower-powered one will be enough.
http://eportal.apexmicrotech.com/mai..._amps/MP39.asp

jw

steamer wrote:
--Looking for a variable frequency drive, A/C but I don't need a
huge one. The application is to drive something other than a huge motor (I'm
fooling around with frequency-controlled color change of electroluminescent
wire) so something that can drive a small motor is all I need. Anyone got a
recommendation?

A VFD is probably a bad choice. They typically work at a fundamental
frequency higher than 60 Hz, switching that wave on and off in various
fashions (i.e. PWM or PCM) to emulate the lower frequencies. The motor
load filters out the higher frequencies.

Since the EL wire responds to frequencies up to 5 kHz, you might find
that the switching frequency of the VFD is dominant. So no matter how
you dial the frequency setting on the VFD, the EL wire may act the same.
You could add a big inductor to the circuit to filter out the high
frequencies, and the EL wire might work as advertised.

I left a lot of stuff out, so my explanation is probably not
crystal-clear. But I'd advise against investing in a VFD unless you can
try it with your EL wire first.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

dvt wrote:
Since the EL wire responds to frequencies up to 5 kHz, you might find
that the switching frequency of the VFD is dominant. So no matter how
you dial the frequency setting on the VFD, the EL wire may act the same.
You could add a big inductor to the circuit to filter out the high
frequencies, and the EL wire might work as advertised.
--Aha! Good to know B4 I spend the big bucks, heh. Thanks to one and
all for the input; experiments to follow shortly..

--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
www.nmpproducts.com
---Decks a-wash in a sea of words---