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Followup to the Penn State - Variable Speed Motor Kit Review

Guess I made the referenced post a bit to long since it appears no one responded to the questions. No matter, I'll make this a brief post and only if there are any questions will I provide more details.

With the new VS motor, low-end is 450rpm, high-end is a blistering 6,600rpm. You read that right - 6,600rpm.

I cannot stop the headstock pulley while running or at startup at the lowest setting (450rpm) using a rag wrapped around the handle and applying all the pressure I can. Watts show 346W and current just over 3 amps with all the load I can put on it and only slightly slowing it down. Can't have two hands wrapped around a handle and hold a digital tach but if I managed to lower it by 100 rpm I would be surprised. That is one stout motor.... I definitely got the handle a tad warm during the test but the motor housing was cool to the touch. I couldn't get to it but I'll bet the large heatsink in the controller box was warming up though....

I did a series of tach readings for each step on the pulleys and positioning the variable speed dial at the Min, 1/4, 1/2, 3/4 and Max positions. The dial is fairly linear. The low speed pulley goes from 450rpm to 1015rpm and placing the dial at the guesstimated 1/2 position yielded 720rpm. I recorded all the steps and dial positions but I left the paper out in the shop and its raining right now - so I'm not going after it.

I initially borrowed a digital tach from a friend that owns an auto repair shop to make the measurements and decided that is one handy tool to have around - so I went looking for one. You would think that the auto parts centers would have these - nope. Ended up at Harbor Freight of all places and they had one model ($69). Compared it with the one I borrowed from my friend which I know (now) cost a wee bit more - and got near identical readings plus/minus 5 rpm. Close enough.

Now, I'm wondering - what is it I can turn using the new high-end turbo speed of 6,600rpm that I have.............?

Bob S.

Reply to
BobS
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I would exercise extreme caution with that top end speed - maybe OK on a pen but nothing much larger in diameter - I would just avoid that pulley combination - with anyting with a reasonable diameter (say 5 to 10 inches) you are at some reasonable risk of blowign it apart by centrifugal force and causing all sorts of damage to nearby objects, and people, including yourself

Reply to
William Noble

My guess is that you are at least twice the speed you should be at. The low speed is much too fast for large out of ballance objects, and the normal max should be about 3000 RPM, I suggest you use another set of step pullies to get the speed down so that you max speed is in the 3000 to

3500rpm range and the low speed around 100rpm.
Reply to
No Way

IMHO, one of the values of a digital control is to have very slow speeds..

Can the pulleys be changed?

For my uses, I'd love to have a 150 to 2,200 range... YMWV

mac

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Reply to
mac davis

The kit comes with a 3 step pulley which is used on other conversions but for the Jet and Delta midi's the instructions state to re-use the original pulley. Now on a midi with a 10" swing and no outboard capability, do I really need to go below 450rpm for roughing? Not like I'll be swinging green tree trunks on this wannabe OneWay....;-)

I just finished testing with the 3 step pulley that came with the kit. The smallest pulley on it is about the size of the 2nd step on the original pulley. I adjusted the 3 step pulley to align with different steps of the headstock pulley and the lowest rpm I could get was 850. No combination would go lower.

After looking at the stock pulleys, I would seriously doubt a smaller pulley could be machined than what is already on the stock unit. Perhaps with some research, one could get the controller to output a lower voltage/current ratio but at some point heat is going to damage something. You don't get a high quality DC motor conversion kit for $85 but what it is - certainly appears to be a reasonable trade-off.

Bob S.

Reply to
BobS

YES!! lol... I've turned some pretty big stuff on a mini and the middle of the bowl might be going 450, but 8 or 9 inches out it seems like about 1,000... Also, for sanding hardwoods, the slower the speed the less heat you generate...

My jet 1442 has 450 as it's slow speed and I'd really like to at least cut that in half..

That's a very reasonable price... I'm assuming that you also had to go to a 220v motor?

Some day, I'll either convert my jet to digital or buy a Nova Dx... not sure which, but from what I've seen it's about $500 to $700 for the motor and controller and $2,000 for the Nova, which is 16' swing and has all the bells and whistles... Gotta sell a lot of pens and stuff before I can consider either upgrade, though...

mac

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Reply to
mac davis

Mac,

Your comment about the edge of a bowl (or other large object) going much faster is a point I didn't even consider but of course, you're right - the speed would be greater. As for the VS motor power being 220 - no, it's

120V.

For $85 (on sale now) it's an okay deal and even though I don't have a lower speed than 450rpm, the plus side is I have 6,600rpm on the top-side. Wanna race........;-)

I just finished making up a couple of new speed charts to stick on the lathe to replace the old ones which are now obsolete due to the VS motor. I have made a warning about using the two last step positions that provide rpm's that are beyond safe and into scary...

Also took the stock motor apart today (the one that was doing the back stroke during the flood last year) to see if it would be worth throwing some bearings at myself. So after a couple of hours of cleaning out the crude and carefully cleaning inside and out - it looks like a brand new motor. Two bearings ($16) were dead simple to replace on this stock motor and a little spray sealer to prevent future rusting on the rotor and I was ready to fire it up. I now have a spare 1/2hp Chiwaneze motor sitting on the shelf. I like the variable speed kit so I'll keep it.

Bob S.

Reply to
BobS

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