Leslie custom speed control help?

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Hi, I'm looking to build a device to control the speed of my leslie speaker
rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
AC motors. I've heard of connecting a standard dimmer switch with mixed
results and the possibility of introducing audible hum. Any schematics or
specs would help greatly.

Thanks,

Aras
 
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Aras Buntinas <aras-NO@SPAM-wcwps.com> wrote:
>Hi, I'm looking to build a device to control the speed of my leslie speaker
>rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
>AC motors. I've heard of connecting a standard dimmer switch with mixed
>results and the possibility of introducing audible hum. Any schematics or
>specs would help greatly.

A standard dimmer would be bad news, but a ceiling fan motor control would
probably do the job. It _will_ introduce buzzing all over the place, but
that's part of the charm. Try your local hardware store.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 
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In article <O6I4d.354279$8_6.268591@attbi_s04>,
Aras Buntinas <aras-NO@SPAM-wcwps.com> wrote:
>Hi, I'm looking to build a device to control the speed of my leslie speaker
>rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
>AC motors. I've heard of connecting a standard dimmer switch with mixed
>results and the possibility of introducing audible hum. Any schematics or
>specs would help greatly.

If it was my 31H, I'd think twice about trying anything other than a
unit designed for leslie speed control. What you (might) save by trying
other speed controls not designed for this you will probably lose when
you have to replace the motor.

In fact, I'm going to bite the bullet and put a Caribbean Controls Two
Speed Conversion Kit <http://www.speakeasyvintagemusic.com/caribbeanstore.html>
in my 31H. An alternative would be the Hamptone MK1C (available from
<http://www.bborgan.com> ) but according to tests run by Mike Casino
the Caribbean Controls unit is a bit easier to install and set up and
works a little better with older motors. You can see the results of his
testing at <http://groups.yahoo.com/group/hammond_zone/> (the message
number is 23488 but you have to be a member to access it).

-ray
 
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Ray Abbitt wrote:


> in my 31H. An alternative would be the Hamptone MK1C (available from
> <http://www.bborgan.com> ) but according to tests run by Mike Casino
> the Caribbean Controls unit is a bit easier to install and set up and
> works a little better with older motors.


Bet it's just a lamp dimmer.


"The Hampton Motor Control performs this by synchronously switching the
power on / off to the motors at precisely the correct intervals to
achieve reduced speeds from a single speed motor."

Sounds like an SCR to me.


"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
detectable failure to the unit and voids the warranty."

But they say it doesn't hurt it if you plug it in backwards.
 
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<< Aras Buntinas" aras-NO@SPAM-wcwps.com
Hi, I'm looking to build a device to control the speed of my leslie speaker
rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
AC motors. I've heard of connecting a standard dimmer switch with mixed
results and the possibility of introducing audible hum. Any schematics or
specs would help greatly. >>

Captain Foldback's site has schematics, pinouts, pics and a section on
the "Tall Boys" and single speed leslies. There were a couple different
versions of the 31H.

http://www.captain-foldback.com/

Goff Proffesional has these Single Motor to Two speed Conversion Kits.
At $269 not that cheap, but a lot easier than swapping out the motor.

http://www.goffprof.com/shopping.jsp?p=140

This is the Hammond-Leslie FAQ index. The FAQ is really excellent and
required reading for a Hammond Leslie user.

http://theatreorgans.com/hammond/faq/

And the "Hammond Tonewheel Organ WebRing".

http://u.webring.com/hub?ring=hammond


Will Miho
NY Music & TV Audio Guy
Off the Morning Show! & sleepin' In... / Fox News
"The large print giveth and the small print taketh away..." Tom Waits
 
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S O'Neill <nopsam@nospam.net> wrote:
>
>"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
>WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
>detectable failure to the unit and voids the warranty."

Man, that is the most hilarious threat against reverse-engineering that
I have ever heard of.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 
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"Aras Buntinas"
> Hi, I'm looking to build a device to control the speed of my leslie
speaker
> rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
> AC motors. I've heard of connecting a standard dimmer switch with mixed
> results and the possibility of introducing audible hum. Any schematics or
> specs would help greatly.
>
>

** Try using a "variac" - ie an adjustable AC transformer.




.............. Phil
 
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Thanks for you help.

Aras


"Aras Buntinas" <aras-NO@SPAM-wcwps.com> wrote in message
news:O6I4d.354279$8_6.268591@attbi_s04...
> Hi, I'm looking to build a device to control the speed of my leslie
speaker
> rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
> AC motors. I've heard of connecting a standard dimmer switch with mixed
> results and the possibility of introducing audible hum. Any schematics or
> specs would help greatly.
>
> Thanks,
>
> Aras
>
>
>
 
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In article <cj1666$2su$1@panix2.panix.com> kludge@panix.com writes:

> >"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
> >WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
> >detectable failure to the unit and voids the warranty."
>
> Man, that is the most hilarious threat against reverse-engineering that
> I have ever heard of.

Could it have something to do with the fact that typically an
oscilloscope has one side of its input connected to the scope ground
which gets back to the AC power ground through the chassis? Connecting
one side of the output of the Hampton Motor Control to the power
neutral (though the ground-to-neutral bond) might make it unhappy.

Of course there are ways to isolate a scope input from chassis/power
ground.

Might a variable frequency source be a better (and more expensive)
method of controlling the speed of this Leslie motor?

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
 
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Scott Dorsey wrote:

> >"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
> >WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
> >detectable failure to the unit and voids the warranty."
>
> Man, that is the most hilarious threat against reverse-engineering that
> I have ever heard of.


Plus, the warranty probably expired 20 years ago.
 
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Scott Dorsey wrote:

> S O'Neill wrote:

> >"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
> >WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
> >detectable failure to the unit and voids the warranty."

> Man, that is the most hilarious threat against reverse-engineering that
> I have ever heard of.

Maybe it's just really senstitive to unloading.

--
ha
 
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hank alrich wrote:
> Scott Dorsey wrote:
>
>
>>S O'Neill wrote:
>
>
>>>"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
>>>WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
>>>detectable failure to the unit and voids the warranty."
>
>
>>Man, that is the most hilarious threat against reverse-engineering that
>>I have ever heard of.
>
>
> Maybe it's just really senstitive to unloading.


un-huh.
 
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In article <znr1096034459k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
>> I have ever heard of.
>
>Could it have something to do with the fact that typically an
>oscilloscope has one side of its input connected to the scope ground
>which gets back to the AC power ground through the chassis? Connecting
>one side of the output of the Hampton Motor Control to the power
>neutral (though the ground-to-neutral bond) might make it unhappy.

That's why you got the differential input module on Tek scopes. Of course,
since the AC power ground _is_ tied to the reference ground, you don't really
need it and you can just pick off the black wire on the output with the
high-Z probe and let the ground pin on the probe float.

>Might a variable frequency source be a better (and more expensive)
>method of controlling the speed of this Leslie motor?

Yes, definitely. You still will only get a limited range of speeds, though,
and the motor will still get hot when it's slowed down too much (since the
motor windings will have less impedance at low frequencies, more current
will flow through them). But, you can speed up as well as slow down.

The right way to do it is to replace the motor with one that is designed for
speed control, but that's a lot more expensive.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 
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In article <pPCdnbR2ZOnOJ87cRVn-og@omsoft.com>,
S O'Neill <nopsam@nospam.net> wrote:
>Ray Abbitt wrote:
>
>> in my 31H. An alternative would be the Hamptone MK1C (available from
>> <http://www.bborgan.com> ) but according to tests run by Mike Casino
>> the Caribbean Controls unit is a bit easier to install and set up and
>> works a little better with older motors.
>
>Bet it's just a lamp dimmer.
>
Most lamp dimmers are extremely unhealthy for motors (and I know this
from experience). Most lamp dimmers actually provide only one half of
the AC waveform. Motors tend to have extremely low torque and run very
hot on most lamp dimmers. And at least back in the late 60's/early 70's
experimentation with lamp dimmers and Leslies was less than successful.
At least back then new motors were relatively inexpensive and there were
lots of motor shops around that could rewind them.

>"The Hampton Motor Control performs this by synchronously switching the
>power on / off to the motors at precisely the correct intervals to
>achieve reduced speeds from a single speed motor."
>
>Sounds like an SCR to me.

Probably not an SCR. SCR controllers (usually) provide half wave rectified
pulsed power.

>"CONNECTING AN OSCILLOSCOPE TO THE OUTPUT OF THE HAMPTON MOTOR CONTROL
>WILL PERMANENTLY DAMAGE THE UNIT! This causes a very specific and
>detectable failure to the unit and voids the warranty."
>
>But they say it doesn't hurt it if you plug it in backwards.
>
Well, I can see where grounding one half of the output (which some people
are likely to do with a grounded scope probe) could cause a rather abnormal
failure. But that is pretty easily avoided. Guess I'll have to take a look
at a friends unit and see what the waveform does look like. I suspect it is
a variable amplitude pulsed waveform and that the Carribean unit is a fixed
amplitude variable pulse width waveform. (This based on observations that
the Carribean unit has better starting torque and runs the motor cooler.)
Either way, I've had bad experiences with lamp dimmers and Leslies, and
I don't feel like destroying any more motors. They aren't as easy to come
by as they once were. So I'm going to go with the Carribean Controls unit.

-ray
fixed
 
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Phil Allison wrote:
> "Aras Buntinas"
>
>>Hi, I'm looking to build a device to control the speed of my leslie
>
> speaker
>
>>rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
>>AC motors. I've heard of connecting a standard dimmer switch with mixed
>>results and the possibility of introducing audible hum. Any schematics or
>>specs would help greatly.
>>
>>
>
>
> ** Try using a "variac" - ie an adjustable AC transformer.
>
>
>
>
> ............. Phil
>
>
>
I've been using a Variac on a one-speed Leslie 46 for a
couple of years.
Works well (knock on wood), although several people on
this NG warned that it was a bad idea.

--
--
John Noll
 
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"John Noll"
> Phil Allison wrote:
> > "Aras Buntinas"
> >
> >>Hi, I'm looking to build a device to control the speed of my leslie
>
> > ** Try using a "variac" - ie an adjustable AC transformer.
> >
> >
> >
> I've been using a Variac on a one-speed Leslie 46 for a
> couple of years.
> Works well (knock on wood), although several people on
> this NG warned that it was a bad idea.



** It is such a good idea they had to knock it out of spite ?




............ Phil
 
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"Scott Dorsey"
> Mike Rivers

> >Might a variable frequency source be a better (and more expensive)
> >method of controlling the speed of this Leslie motor?
>
> Yes, definitely. You still will only get a limited range of speeds,
though,
> and the motor will still get hot when it's slowed down too much (since the
> motor windings will have less impedance at low frequencies, more current
> will flow through them). But, you can speed up as well as slow down.
>


** A commercial VFD ( variable frequency drive ) scales the the AC
voltage as well as the frequency to keep the motor current constant. Output
frequency typically varies from as low as 0.1 Hz to 300 Hz - so a very
wide range. The high end is more of a worry as the motor may overspeed and
be damaged by high centrifugal forces.

A Google search will turn up dozens of them on offer - starting with units
rated for 150 watts and single phase.




.............. Phil
 
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John Noll <jn145@verizon.net> wrote in message news:<41544AAB.3050802@verizon.net>...

> >
> >
> I've been using a Variac on a one-speed Leslie 46 for a
> couple of years.
> Works well (knock on wood), although several people on
> this NG warned that it was a bad idea.
>
> --

what's so bad about a variac? i'm in the process of putting variacs
on both motors of a 2motor leslie . . .

chris deckard
saint louis mo
 

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Aras,
You might want to check into a company called RTCLogic. MCv2 Motor
Controller. Though I haven't yet installed one in a 31, I have installed
a few in 21 & 22H's. As a matter of fact, I installed one in Dave
Martin's 21H at his studio in July 2003. Never had a callback. Give him
a call or email him for feedback on it. You can go to RTC's website:
http://www.rtclogic.com/ for more info as well. One nice added feature
is that this controller does away with the relay. So those pops & clicks
are history. Hope this is of some help.
Murph









In article <O6I4d.354279$8_6.268591@attbi_s04>,
"Aras Buntinas" <aras-NO@SPAM-wcwps.com> wrote:

> Hi, I'm looking to build a device to control the speed of my leslie speaker
> rotors. It's a model 31H Tall-Boy and only has the single-phase one speed
> AC motors. I've heard of connecting a standard dimmer switch with mixed
> results and the possibility of introducing audible hum. Any schematics or
> specs would help greatly.
>
> Thanks,
>
> Aras
>
>
>
 
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On 25 Sep 2004 20:32:26 -0700, chrisdec@swbell.net (mr c deckard)
wrote:

>what's so bad about a variac? i'm in the process of putting variacs
>on both motors of a 2motor leslie . . .

I think all these caveats are just good practical conservativism. No
motors like being throttled back, including gasoline auto engines.

The difference is that auto engines are designed to survive it.
Ordinary electric motors must suffer in silence.

No solution, including variac, phase angle or cycle counting is
without some penalty to the motor, and the relative penalties vary
with the amount of speed reduction.

Has anybody done a conversion to synchronous or stepping motor?
Maybe a modern "DC" motor would be easier.

Chris Hornbeck
 
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