New motor help

That looks like a two speed motor. Likely a single winding with a Dahlander connection. You will want to go three phase with a vfd to duplicate the torque and hp. Since the frame is so large, I'd look for a 184 frame 5 hp to replace the motor. That will give you higher torque at any speed than the original and allow for a wider rpm variation using the vfd. The gear choices negate that somewhat so a really good deal on a 3 hp would also work fine but I've found that 5 hp motors are often priced as low as the 3 hp and your lathe will handle it.

Dave
 
Thanks everyone.
I'll go with a 3ph and vfd.
I'll also check the suggested sites for motors.
 
I would stay with a 3Hp motor if you have a gearbox. I would run off off a VFD and you would have the same Hp at 30Hz as you would at 60 Hz, motor would be constant torque.

Use a inverter rated 1750 RPM motor 3 Hp, this is an inverter vector type which has a wider speed range ($168). The cost is mostly shipping.

There are others listed, if you have a question on one please post a link. Be careful, I had another motor posted, when I checked the specs it had no base/foot. Always check the motor specs online as to the cooling, Hp, voltage, RPM, etc. as they often leave out critical information. Do not assume, always ask if you are unsure.

VFD, these are reasonably priced and fairly straight forward to program. I can provide some general parameters if needed. I recommended making any parameter changes through the software.
GS21-23P0 DURApulse GS20 series AC general purpose drive, enclosed, 230 VAC, 3hp with 1-phase input, SVC, V/Hz, FOC or torque mode $253

Total cost of VFD + motor would be $600-700, but a VFD in this application is NOT a 3 phase power source and requires some knowledge to rewire the machine. Phase Perfect does sell 3 phase power sources that are more less plug and play and similar cost to an RPC, but the issue will still be that the controls are for a different voltage and also the wiring is for the specific 2 speed motor that came with the machine. It is possible to use a step-up transformer but you really do not want to be working with 575VAC and you still need to generate 3 phase. VFD with a good 240VAC single speed motor is your best option in my opinion.

I see you are in Canada, sourcing a motor may be more of an issue to get one shipped to you. Automation Direct I believe ships to Canada. Seems like a lot of high voltage machines are in Canada, this comes up frequently.
 
Last edited:
3 phase is definately my recomendation. I converted my Clausing 100 to 3 phase and a Huanyang VFD. So far it is exactly what I wanted. I messed around on Ebay looking for new and used motors and the cost of a 2 hp 3 phase motor was through the roof. Some new ones as much as $1100 usd. I found a perfectly good one at a place about 10 miles from me that buys equipment and steel from plants that are selling them for scrap or liquidating everything. I bought a 2hp working and very quiet 3 phase for $55usd. When buying used motors look for the ones that have had the power wires cut rather than disconnected. Disconnected usually means replaced with a good one. Cut wires usually means was working when removed. I am not sure where you are located but the address and phone number to the place is

  • S&T Steel 4187 Airport Dr, Wichita Falls, TX, United States, Texas
    7KDVc3hw483.png

    phone (940) 855-4221

  • Ask for Stan or Matt great people to deal with.

  • Here is the motor and Huanyang vfd

 
My recommendation for a 5 hp motor is based on opportunity cost. I watch for NOS motors and although tougher to find in Canada, it pays to search. This Baldor ECP is new and cost 250 USD shipped. The Marathon was about the same and is a vector duty that is twioce as expensive and beyond what you need. The point is you can find deals on motors. I seldom advise going to a larger motor on a new lathe as value engineering has matched the build to the motor much more closely than on an old machine. English machines like the Colchester Student were overbuilt relative to the motor installed. I suspect that the cost and availability of amps in the UK put larger motors beyond the market. Look for the best deal on either hp ( the frame size will likely be the same-184). Dave
 

Attachments

  • DSCN4201.JPG
    DSCN4201.JPG
    225.4 KB · Views: 6
  • DSCN4202.JPG
    DSCN4202.JPG
    229.3 KB · Views: 6
  • DSCN4148.JPG
    DSCN4148.JPG
    230.2 KB · Views: 6
I would stay with a 3Hp motor if you have a gearbox. I would run off off a VFD and you would have the same Hp at 30Hz as you would at 60 Hz, motor would be constant torque.

Use a inverter rated 1750 RPM motor 3 Hp, this is an inverter vector type which has a wider speed range ($168). The cost is mostly shipping.

There are others listed, if you have a question on one please post a link. Be careful, I had another motor posted, when I checked the specs it had no base/foot. Always check the motor specs online as to the cooling, Hp, voltage, RPM, etc. as they often leave out critical information. Do not assume, always ask if you are unsure.

VFD, these are reasonably priced and fairly straight forward to program. I can provide some general parameters if needed. I recommended making any parameter changes through the software.
GS21-23P0 DURApulse GS20 series AC general purpose drive, enclosed, 230 VAC, 3hp with 1-phase input, SVC, V/Hz, FOC or torque mode $253

Total cost of VFD + motor would be $600-700, but a VFD in this application is NOT a 3 phase power source and requires some knowledge to rewire the machine. Phase Perfect does sell 3 phase power sources that are more less plug and play and similar cost to an RPC, but the issue will still be that the controls are for a different voltage and also the wiring is for the specific 2 speed motor that came with the machine. It is possible to use a step-up transformer but you really do not want to be working with 575VAC and you still need to generate 3 phase. VFD with a good 240VAC single speed motor is your best option in my opinion.

I see you are in Canada, sourcing a motor may be more of an issue to get one shipped to you. Automation Direct I believe ships to Canada. Seems like a lot of high voltage machines are in Canada, this comes up frequently.
I did not see a shaft diameter on the motor listed here. Buyer certainly needs to know that. What made the motor so expensive on my Clausing 5913 was it was just over 1 inch in diameter and most 2 hp 3 phase are 3/4" diameter or less. Clausing is the mother of the Colchester. My Clausing 5913 has a hydraulic variable Reeves Drive pulley system on it. Only the correct shaft diameter will work if a person keeps the Clausing drive system. I do not know if the Colchester has the same variable drive system or not. As you may remember I used a VFD on my Clausing 100 but not on the Clausing 5913. Torque is an issue when varying speed on electric motors. So I have the best of both worlds with the 5913. It is hated by many who do not understand the principle. The principle is constant RPM of the motor (1800) The spindle speed ( 52 rpm all the way to about 2100 rpm with constant torque) is varied by the variable diameter of the Pulleys. I do not know how much you know about lathes, but it would be prudent to get to know the Colchester before making a decision on how you want to go.
 
.Itlvt makes a really good point and I should have talked about this before discussing motor choices. Colchester made a million options for the Student lathe. While I don't believe a reeves type drive was part of the drive train, the two speed motor in your picture was a rare option. The shaft will probably be a different diameter on any replacement so you need to examine the pulley to see how easy the fix is. The motor plate might also need modifying. Most important is the lathe may and probably was fitted with an electric brake. There is considerable wiring knowledge in making this conversion so my experience is that you are underestimating the cost and time involved in doing it well. My Smart Brown had a similar three speed motor and brake that needed to be removed and used a similar Matrix clutch. The pulley was rebored and a motor plate was made. MKSJ here did the vfd conversion for me and it works beautifully but the cost and time is not insignificant unless you have lots of mechanical and electronic experience. My lathe was also a 550v machine but had a bad winding on the motor so I had no choice in the fix.

These pictures have been posted before but give you an idea. If there is any way to take the lathe to someone with appropriate three phase for testing, I'd recommend it. A pain to do but if the motor is good on both speeds, the brake and clutch works, etc., you need to at least consider the option of a small rotary converter and transformer. That might be a reasonable option.
 

Attachments

  • DSCN3903.JPG
    DSCN3903.JPG
    232.5 KB · Views: 6
  • DSCN3913.JPG
    DSCN3913.JPG
    240.7 KB · Views: 7
  • DSCN4084.JPG
    DSCN4084.JPG
    232.7 KB · Views: 7
  • DSCN4095.JPG
    DSCN4095.JPG
    213.9 KB · Views: 6
  • DSCN4121.JPG
    DSCN4121.JPG
    231.6 KB · Views: 7
Within Canada, the company below has an extensive line of electric motors, the Teco below is reasonably priced and they have multiple distribution points in the country. The Teco motor in the eBay listing would still be my recommendation if the shipping charges are not prohibitive. Shaft diameter can be an issue if there is a proprietary type of pulley that cannot be either bores or sleeved to except a different shaft diameter. Typically a particular motor frame size is associated with a standard shaft diameter but there are many special order variants. A 3Hp 182T/184T is usually 1.125". If one has a limited number of headstock speeds or some form of CVT/Reeves drive that will be removed, then a larger motor would be needed, but one motor cannot effectively cover the full speed range, and the associated cost of a VFD goes up significantly.
 
I've been considering doing a VFD on a SB 10k that I have. The reason for doing this is that I don't have 3 phase in my home shop. I also want to add an emergency stop which I researched and can be done w/ a VFD. I've heard that the VFD should be slightly oversized for motor being used. What is best practice on VFD selection? Also, how long will original motor last?
 
Back
Top