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I have 2 older Woodman 30 frame radials. They are in the process of restoration for next year.

Does anyone have an idea or what parts would be needed to change it from the mechanical speed control to electronic?

I heard someone mentioning a router speed control in another thread.
 

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The best solution is a variable frequency drive (VFD). They work on regular AC motors. Router speed controls usually only work on brush type motors (Universal motors) and you lose torque. VFDs maintain torque down to very low RPMs. You can find them on Ebay and at places like http://www.driveswarehouse.com. They are not particularly cheap. Make sure you get one for the type of electricity you can supply and the output that you need. Don't 440 volt if you don't have that. If the motor is single phase, make sure the output will supply single phase. A common usage is to convert single phase power into 3 phase so you can run a 3 phase motor.
 

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I've seen those mechanical controls only once. It seemed robust and worked fine. Before you mess around, why not see how they work out? After all they have probably processed a lot of honey.

Dickm
 

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Discussion Starter #4
I may leave one mechanical control alone. But the other requires some rubber pieces replaced and I doubt if there is anything that will replace them. One is a rubber drive wheel.

And they have indeed extracted a bunch of honey in their day. And will extract tons more!

Thanks
 

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not sure what you got, but if it has a motor, just go to radio shack and get a rheostat or potentiometer like a volume knob and insert it in series on one of your leads to the motor. better yet, have an electrician-friend do it for you -messing with AC is ALWAYS risky. sorry if I misunderstood
 

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Is Woodman still in business? If so I'd bet the drive parts are available. I have a similar drive on my Kelley. BTW the Kelley basically has 3 speeds (speed control lever locks in one of 3 positions). I haven't remembered to call for an owner's manual; any tips from someone that has one on the speed changes, time in each (& total extracting time)?

BTW a simple potentiometer or volume control would probbly not be near heavy enough; also most AC motors aren't happy with lower voltage & have much less power even if they will start.

Thanks!

Lew
 

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Discussion Starter #7
I do not believe Woodman is still around. If I could get the rubber parts then I would not consider the conversion for quite some time.

Lew is correct.... any rheostat system would tap power at low RPM's/

I am hoping someone out there made their own variable frequency drive out of Radio Shack parts. The VFD's I've seen are spendy.

I can afford up to $200.00 per extractor but can not tell by the descriptions on the site Ross gave which one is right for 115V input and 115V output and power a 1/2HP to 3/4HP AC motor.
 

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Sundance - check out "diac/triac" high-amperage
light dimmers as used in theater lighting. They
can handle the inrush current of a motor just
starting out at high tourque and low RPM, and
give you a "volume control", just like a big
honking rheostat.

Just remember that heat sinks are required for
every triac or diac, and that one can never be
too picky about thermal grease between a
power device and a heat sink.
 

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Discussion Starter #9
Thanks Jim.... Sounds interesting. Inexpensive enough to try out for sure.
 

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May bee a long shot but IIRC the "Little Wonder" extractor in years gone by could bee bought with Woodman or Dadant's name on it. Woodman may have made other extractors for Dadant so I'd check with Dadant & see if they have the drive parts you need.

Lew
 

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This is for anyone with AC motor knowledge. I built a bee-vac last night and I have a small shop vac that I am using for the suction. I wired a rheostat (a light dimmer switch) in line to adjust the motor speed. It seems to work fine but I only ran it for a minuet or so. I then did a little reading on the internet today and found that this may be a bad idea unless I have a universal motor. Is there anyway to know what kind of motor is in the shop vac? Also if I have a three phase AC motor what will happen if I continue to use the rheostat?
 

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I'd just put an adjustable damper on somewhere to let outside air into the vacuum. That way you won't be overheating the motor or the rheostat.

I've always thought it would be interesting to understand how AC motors work (as opposed to DC motors which I've built before). But I'm afraid they are still a mystery to me.
 

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the proper way to control the speed of an AC motor is to vary the frequency of the juice you drive it with. by reducing the voltage you are just underpowering it so that it can't run at it's design speed. not really a good idea.
unfortunately, a variable frequency controller is expensive.
what you really want to do is take the AC current coming out of the wall and run it thru a rectifier (cheap) and make it into DC, then use a DC motor which you can control with a rheostat (cheap).
of course for Sundance this is impractical because it involves replacing the motor which is non-trivial. I'm thinking of building an extractor over the winter and driving it with a variable speed 1/2" drill. they use the above rectifier/rheostat scheme

Dave
 

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Discussion Starter #14
Actually... I am in the garage door business and have several smaller DC 1/2 HP motors. Not sure if they are large enough to drivea 30/6 frame reel.

I am all for the VFD but the types and different models are baffling and are not described well for the lay person.

I know I need 115V in and 115V out in single phase. Seems most VFD's are bent on converting the voltage and/or phase. 115V units appear to be rare.
 

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Good idea Dave......... I am just kicking it around now as they are torn down and the exteriors are bein sprayed (by me) with spray on truck bed liner.

Won't fire these old gems up until next season.
 

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Just a thought - I bought a motor built for a treadmill from <http://www.surpluscenter.com>. I don't remember for sure, but I think it was only about $25 (5 or 6 years ago). It came with a little circuit board to convert from 120v AC to whatever it needed in DC and included a speed control. I just needed to mount the circuit board in a box with the speed control knob sticking out and I was in business. The nice thing about DC motors is that they have full power at any speed, or so I've been told.
 

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I used my rheostat described in my post above for my bee vacuum and it seemed to work. No excessive heat to speak of and I ran it for a few hours. It was really easy to adjust the flow for optimum sucking. I found out by cruising the net that 80% of small AC motors are “universal” or “variable speed” motors and work much the same as DC motors and will actually run on DC power. I don’t know that this is true as I found it on the internet but it was enough to convince me that my configuration was good enough.
 

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drobbins sezs:
I'm thinking of building an extractor over the winter and driving it with a variable speed 1/2" drill. they use the above rectifier/rheostat scheme

tecumseh replies:
this is exactly how I power my small extractor. I acquired an old electronic bench voltage regulator (about the size of an old telephone with a dial on top) to control the speed.

if you use a rheostat on an ac circuit you are suppose to place it across the neutral (white) circuit.

if I was attempting to drive a large extractor I would be very likely to utilize a dc motor (high torque at all voltage inputs). they have lots of dc motors and speed controllers at surplus center which txashurst has previously mention. they also sell pentometer (spelling??? but very cheap) which allows you to convert ac to modified dc power which with the addition of a simple rheostat allows you to build your own speed controller. it seem to me the dc speed controllers units provided by surplus supply were also fairly inexpensive.

if I have serious questions (such as sizing components) I go to my local electronic wizard (he is definitely not an electrician).
 
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