My 10EE VFD Conversion

[will.mcray]

I looked and have lots of sizes but not 92. I pick them up on ebay. Gates Tripower are uniform enough that you don't need a matched set. Dave

Thanks for checking Dave.

Will


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[mksj]

Very nicely done, and clean install. Great combination of the Marathon motor and use of the backgear for this lathe.

I assume you are using a 1000 ohm speed pot. On the braking resistor if you need a bit more braking power, you could go down to 17 ohms, I did a recent complete control system build for Dave's CVa lathe with the same VFD and used the resistor below mounted behind the back plate due to the size of his electrical cabinet. I have not seen the use of a thermal overload relay used for VFD, they are usually more tailored to motor overload curves as opposed to VFD, if used for single phase they usually include a jumper and wiring as shown below. Some have phase loss detection and all three phases the the overload relay need to be powered. Most of the time I prefer to use either semiconductor type fuses if 3 phase input power and low peak fuses in single phase due to the higher current draw peaks with single phase. In this size VFD I use the J class fuses vs. the CC, but the fuse holders are pretty big. Also be careful of rapid cycling of the VFD is it shuts down, wait at least 5 minutes before powering back up as this allows the current inrush circuit to restart properly.

https://www.mouser.com/ProductDetail/TE-Connectivity-Holsworthy/TJT50022RJ?qs=Rv6LVDxB0Zqv8BuN7KM9xw%3D%3D&countryCode=US&currencyCode=USD

 

[Cal Haines]

Like many, I have experienced M/G issues and was helped by Cal (10EE Whisperer) and narrowed the issue down to the rheostat. Searching high and low, I could not find any so I made the decision to convert to AC and VFD.
...

Very nice work Will!

I want to clarify one thing. I located a rheostat for Will at TAS Iron LTD, in Berea, OH. Tim, the owner, is in the machine tool rebuilding business and specializes in VFD conversions. He does a lot of 10EE rebuilds and has used rheostats in addition to other 10EE drive parts available. The problem is that he's a busy guy and very hard to get hold of. IIRC, Will was finally able to get him on the phone and Tim was going to sell him a rheostat ($25 plus shipping), but never followed through, despite multiple phone messages from Will.

The problem with Will's rheostat is that the windings opened up at a joint between windings. (10EE rheostats use multiple sections of windings to produce a non-linear profile.) Other people have been able to repair an open like that, but it depends on two sections in question (conventional solder won't stick to some of the wire that was used). Will is going to send me the rheostat so that I can look into the problems involved.

 

[WaltDizzy]

There's a rheostat for sale at troutunderground. The owner is asking $200 for it.

 

[will.mcray]

There's a rheostat for sale at troutunderground. The owner is asking $200 for it.

Well that ship has sailed for me. It a risk if the seller can’t tell you if the rheostats are any good.


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