Matt offered me a 3ph motor Now wiring the VFD?

I have desided to go with a new 3ph upgrade from Matt. The caps didn’t work so mat thinks the centrifical switch is dead. Now while I was researching 3ph conversion, I saw a post on wiring the PM932 forword, stop reverse switch, and E-stop so as not to release the smoke out of the new parts, being the dummy I am, I didn’t mark it for reference. Now I can’t seem to find it again. Most likely I’ll be using a WJ200 VFD.
Thanks
CH
 
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Hey David
Just a quick question do I need just one 50 ohm 500w braking resistor or do I need one on each phase? Or better yet do I need a braking system at all? I’m not going to cnc this machine just want better control of RPM, and rid of caps and centrifugal switches
CH
 
Being as the resistor is not very expensive, I'd go ahead and get one, when changing tooling or stopping the machine it's nice not having to wait too long for the machine to stop.

Only one required per VFD (machine).

Something like this should work. (you get 2 for the price of 1)
https://www.aliexpress.com/item/2-p...16b0-4076-beba-e04793a89957&priceBeautifyAB=0

These seem very inexpensive, can anyone vouch for their functionality? I thought about installing a braking resistor, but didn't find any that were reasonably priced.
 
The braking resistor is specific to the VFD purchased, the Hp/kW rating, the output voltage and the application it is going to be used for. Some VFDs (like some of the HY, and 240V Teco L510) may have braking resistor terminals but lack the internal circuity to use an external braking resistor. The WJ200-015SF would use a 50-75W 300-500 ohm resistor. These are available on eBay for around $30, or US vendors for about $60. Both will work, and I do not have concerns as to the functionality of either. When building a full control system, I order the braking resistor from Mouser because I do not want to deal with the long shipping times from China, and it is a better quality item. A few other people have had the Chinese resistors arrive broken because of poor packaging.
https://www.aliexpress.com/item/RX2...87c9-4c7f-926d-8339bfa5b69b&priceBeautifyAB=0
https://www.ebay.com/itm/500W-50ohm...-resistance-Dummy-Load-for-Audio/231092889325
https://www.digikey.com/product-det...-amp-connectors/TJT50068RJ/A123925-ND/5878246
https://www.mouser.com/ProductDetai...rIkmrvidAl35n5xACJLyL3b7QF7NLG%2be0H747JwoQ==

VFDs do have internal braking circuity and have a resistor to dissipate some of the excess voltage generated on the buss, but if you attempt to do very quick stops, frequent repeated stops and/or have a lot of momentum in the system the VFD will go into an over voltage error and freewheel to a stop. This is probably less of an issue on a smaller mill and you are running something like 5 second deceleration times. So if you are doing a simple system then you can live without a braking resistor, but if you want quicker stops then it is worthwhile to add. All industrial mill and lathe factory installed VFD systems I have seen have external braking resistors installed. If your VFD has the circuity for an external braking resistor it is relatively inexpensive and adds a safety factor. I am currently building a 935 VFD system which will normally run with 2 stage braking (3 seconds) but revert to 1 stage (1 second) if the E-Stop is pressed. Both of these would not be feasible without an external braking resistor.
 
Thanks for the links. $60 for a quality unit from Mouser is something I would seriously consider, for both my 1340GT and 935TS. I have a Hitachi WJ200-015SF on my lathe and a 022SF on the mill.
 
For info I bought an import resistor for my PM-932 CNC mill with guidance from mksj. It arrived in about ten days and has been working great since I installed it about a year ago.

BTW - my VFD is a Hitachi WJ200-015SF.
 
I'm mot sure I see the benefit of a breaking resistor on a gear head mill. They generally stop quickly on their own and even when power tapping, where I might see some benefit, I never get more than 1 revolution before the spindle stops due to the low gearing.
 
I'm mot sure I see the benefit of a breaking resistor on a gear head mill. They generally stop quickly on their own and even when power tapping, where I might see some benefit, I never get more than 1 revolution before the spindle stops due to the low gearing.

Jay - As you know my mill is very similar to yours; no gears in the headstock. I installed the resistor so I could power tap using a tension/compression tap holder. Before installing the resistor and tapping aluminum at about 400 rpm using a 1/4-20 tap, the spindle would turn 3 to four revolutions before reversing. These 3 to 4 revolutions used up nearly all of the tension travel in the tap holder. With the resistor the spindle stops in less than 1 revolution leaving me with some safety margin on the tap holder.
 
Jay - As you know my mill is very similar to yours; no gears in the headstock. I installed the resistor so I could power tap using a tension/compression tap holder. Before installing the resistor and tapping aluminum at about 400 rpm using a 1/4-20 tap, the spindle would turn 3 to four revolutions before reversing. These 3 to 4 revolutions used up nearly all of the tension travel in the tap holder. With the resistor the spindle stops in less than 1 revolution leaving me with some safety margin on the tap holder.

Hey Tom, I was responding the the OPs use of a resister on his mill which is still a gear head. Maybe I missed it but I didn't think he was converting it to a belt drive? My one-of-a-kind PM-932HD drill press is still a gear head so I was referring to that. I'm interested to see if the 3hp 3 phase motor is a direct bolt on.
 
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