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

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COMachinist

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#1
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
 

Bob Korves

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#3
Simple basic rules. Make sure the VFD is the last thing before the motor. No switches or other controls between VFD and motor. All control wiring must end up at the VFD. The VFD controls the motor. The controls will be low voltage and will go to the low voltage side of the VFD. The high voltage wires only go from wall to VFD and from VFD to motor.
 

mksj

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#4
This would be for a mill, so one would not need relays and would use what is called 3 wire control. This uses momentary switched for the start and stop, and a sustained switch for forward/reverse. Some files are listed, if you indicate what you want then I can give you something more specific. You probably want to put the VFD in an enclosure, but this varies, I have my VFD in my cabinet base. There are some Nema 4 sealed VFD's with a power switch but they tend to be a bit more. There was an older posting specific to the 932, but I cannot find it. We combined the machine control box and rewired things a bit, we added the momentary stop/run switches and rewired the for rev switch to the VFD inputs. The 932 power contactor turned on the VFD power. Check/PM with Jay-Z on what he did. https://www.hobby-machinist.com/threads/pm-932-capacitor-explosion.46096/page-2
Mark


Mill Control 2018.01.25.jpg
 

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Kiwi Canuck

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#5
CH, Mark will get you the info you need, he was an invaluable help with my VFD conversion.

The Hitachi VFD's are very nice and not too difficult to setup.

BTW if you want to do a POD like the one shown above, the enclosure is from McMaster Carr, $28.81. plus shipping.

https://www.mcmaster.com/#7301k37/=1d6pwt1

Or if you are not going to use a tach or mount the tach separately you could consider this less expensive option. $12.00

https://www.automationdirect.com/ad...ghting/Enclosures/Pushbutton_Enclosures/SA111



All the switches 22mm and are from Automation Direct.

Mark has all the part numbers for the switches included in his drawings.

You just need to choose which functions you want, I went with the lighted Emergency Stop and it's great to be able to see the power status from a distance.

Here is mine, tach not installed yet.



Here's a picture during the programming stage once we got it working.
You probably don't need as much as I have in there as I included everything that I might need in the future and the fan just in case, but probably not needed.

David.
 

COMachinist

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#6
Thanks Mark this will help a ton. I got to get every thing together first and then I’ll start.
CH
 

COMachinist

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#7
Nice install David the pictures are great i will be adding a tach so I know what the rpms are.
Thanks
CH
 

COMachinist

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#8
I have the motor paid for and it should be on its way soon. I ordered a Hitachi WJ200-0015fs VFD, the 10 turn pot is coming from Amazon, an I ordered 8/4 shielded cable, for vfd to motor, not sure what I need from the vfd to the remote control box. Got a box like David's POD from McMaster Carr. I have large NEMA steel box for the VFD wall install. I have 8/3 G from Braker box to VFD for L1 L2? Thinking that 16ga shielded will work for the POD. Man when start getting into this, there is a lot to think about, I'm wanting to put a tack on the spindle some place so I know what RPM I'm at as well. Any thing else I need to think about? Other than the million I don't know about. LOL Man I pulled the motor off the mill today and that thing smelt fried. Going to look at the centrifugal switch tomorrow I think the smoke escaped from it last week.
Thanks
CH
 
Last edited:

mksj

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#9
You might look at this old post as to a simple install on the 932. What can be done is to hook-up the VFD power to the main contactor so it works just like the old machine and then just add a pair of momentary switches for the run/stop function. The forward/reverse switch is striped of the high voltage, no connection to the VFD digital inputs is need to run forward, in reverse it makes a sustained contact with input 3. Power cable into the VFD for 2 Hp would only need 12AWG, three phase power to the motor from the VFD would be 14AWG as the motor amps are probably 4-5A. If your 932 does not have powered Z drive then it is probably easiest to just build a complete new system with control pod similar to one of the designs outlined above.
https://www.hobby-machinist.com/threads/pm932-mill-motor-upgrade.64260/#post-534002
 

Kiwi Canuck

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#10
CH, for the POD wiring you can use anything from 22AWG to 18AWG shielded. (16AWG/10C might be a bit expensive if you have to buy it)

You will need minimum 9 conductors for the POD Controls including the Tach. (make sure you get stranded conductors, not solid)

I had some 22AWG 15 Conductor shielded wire left over from a job so I used that.

If you haven't seen my VFD install here's a link, hope it helps. It starts on the previous page post #116
https://www.hobby-machinist.com/thr...ady-to-start-lathe-mill-shopping.51470/page-5

David.

PS don't copy my wiring in post #129, that was backwards and the mill would only run in one direction.
 

COMachinist

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#11
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
 

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#12

Cooter Brown

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#13
Three phase Motors don't have centrifugal switches only single phase motors have those.
 

81husky

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#14
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.
 

mksj

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#15
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.
 

81husky

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#16
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.
 

TomS

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#17
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.
 

jbolt

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#18
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.
 

TomS

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#19
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.
 

jbolt

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#20
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.
 

TomS

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#21
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.
Got it. Sorry for any confusion I caused.
 

COMachinist

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#22
Ok, the WJ200-0015SF arrived today yea looking forward to getting the mill up and running. The motor from mat I assume the is on the way have not seen ant info on the shipping. I sent payment last weekend. Figure it will be here end of the week maybe first of next week. I have some of the instalion items, still waiting on control shielded cable and shielded motor cable. I have 10awg 4 conductor/G already run from the breaker box about 6 ft away I can use as the VFD power. I was really surprised how light and small the VFD is. I was thinking way to big for the wall box for the VFD. I'm trying to read that little boo they sent, but damn my eyes are't as good as they used to be so I printed the PDF file so I could read and see the figures good enough to tell what is what.
CH
 

COMachinist

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COMachinist

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#25
Thanks, for the link Mark. I all ready ordered the other one I posted above. Looks like they are about the same, I looked at the recomended braking resistor for the Model 15 SF and it was from 50 ohms to about 150 ohm form 150%-50% braking torque. If you going to ridged tap you need fast control of the spindle. So I optitid for the 50ohm and 150% braking torque. It also fits my enclosure better than the audio load.
CH
 

COMachinist

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#26
Great news I got the motor today from Matt, (thanks Mat.) I plan to start wiring the mill for the VFD, this weekend. Mat and QMT are top notch with customer service. I could not be happier to have the 3 ph and vfd. Now all i need is to figure out how to not fry every thing in the process.
CH
 
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