Motor and VFD selection for Clausing 6300?

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I SHOULD BE FISHIN

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Hello,

This is my 1st post and have to say great site! I have search here as well as other places and have yet to get the answers I need. I have a Clausing 6300 that has a 1ph 220 motor with no info plate so I don't know the HP. I want to switch it over to a 3ph with a VFD for the variable speed and braking capabilities. What I need to get some help on is what motor to use, I looked at the specs for the lathe and it says 1/2-1/3hp which seems small for this lathe. Before that I was going to buy a 2hp but now am thinking that maybe too big and don't want to break anything (I'm thinking the v belts will slip anyway). So if anyone can point me in the right direction I would be very happy. My searching has lead me to think the Teco FM50 and 2hp 3ph motor should work. I'm not picky on brands as long as its reliable so your advice and links would be very helpful. Thanks in advance.

Stan
 
According to http://www.lathes.co.uk/clausing/page2.html and http://www.lathes.co.uk/clausing/page9.html the Clausing 6300 Series Model 200 came with a 1/3 HP motor for the countershaft lathe, and a 1/2 HP for the variable speed lathe. The HP selection is kind of up to you, but if it were mine, i would put on a 1/2 or 1 HP inverter duty 2 pole 3 phase motor and VFD drive on it. Not having run it, i don't really know if the extra 1/2 HP would really be any help or not.
 
The FM50 202-C VFD is a Single/Three Phase 200-240V (+10%, -15%), 50 / 60Hz (+/-5%) so thats ok as long as you have a 220v hookup, it will convert the 220v single phase into 220v 3 phase so it acts like a phase converter and drive a 3 phase AC motor.

The WEG motor is a 1800 RPM 2 pole continuous duty motor, but its not a vector/inverter duty motor which is an issue. Continuous duty motors should really only be run at their rated speed, in this case 1800 rpm or they will overheat. You can read more about vector/inverter duty vs continuous duty motors at http://motors.automationdirect.com/Information/faq.html

Other than it not being a vector/inverter duty motor, the speed looks to be within 100 rpm of the original motor and since its variable you can pretty much match the original rpm's by lowering the frequency by 1 or 2 Hz. I wouldn't overdrive the VFD to 120 Hz for increased spindle speed unless you are sure that the spindle bearings can handle the increased speed.
 
Thanks for the new info, looks like I have more homework to do! The price of an inverter duty motor really jumps from the general-purpose continuous duty motors. After reading through that link it appears you can run some continuous duty motors as long as you don't run them below there minimum RPM, how can I find what that is? It seem that they point that out on their motors but I would like to shop around. But considering the free shipping this is not far off from my previous pick, http://www.automationdirect.com/adc...Premium_Efficiency_(1_-_300HP)/MTCP-002-3BD18
What do you think? Thanks, Stan
 
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You can normally find the motor specs on the manufactures website although I think WEG's site is a little hard to find information on. Don't take my word for it, but I think you will be ok as long as you keep the rpm up and use gear reduction of the lathe instead of lowering the VFD frequency if you need to slow things down for anything less than 500 rpm or so. The gear reduction will also give you increased torque.
 
Ok thanks, I will probably order my stuff tomorrow. I'm going to take the single phase motor that was on the lathe down to the motor shop and they said they can tell me what HP it is with an amp meter. I will know then what HP to order. I will post the results of the motor and VFD when I install them. Thanks again!!
 
I assume you are planning to use the VFD for speed control as well as to convert from single phase to 3 phase. You should really consider going to a sensorless vector drive rather than the volts/hertz FM50. For a little more money you can get a Teco JNEV. The 2 hp model JNEV-202-H1 is about $30 more than the equivalent FM50 and would be more appropriate for speed control on a lathe.
 
I don't think you really need to use anything special for a motor. VFDs have been hooked up to many different brands of motors with out issue. Many old 3-phase machines have been hooked up to VFDs without a second thought. For the most part the results are good, with out problems.

You seem unclear to the HP of your original motor. You mention taking it to a motor shop to find out. When you do find out, you might want to inquire about a used 3- phase motor of comparable HP. You could get a good deal from the same place. As far as HP goes, Id rather have a bit more than what I can use, rather than less. I have had a lathe that was under powered, and was not happy using it that way.

To go for a increase in HP is OK, as long as your not going excess. If you can run a bigger motor, and it will still fit in the original location, then I would use it. When using a VFD , you generally loose torque when you dial it below 60 hrz. So you should use your VFD for fine tuning to find the sweet spot. Not run the VFD to get very low, or hi rpm. Low rpm will cause heat, the other could cause far worse problems.

Usually the problems start with the guys that say, with my new VFD, I don't need to switch belt locations on my mill, or I don't need to change spindle speeds on my lathe. They use the speed pot on the VFD for everything, big mistake! The vari-speed ability of the VFD is commonly misused.

Nothing wrong with using this feature as long as you keep in mind it can also be one evil or the other. I can see the VFD being used to slow the spindle for threading operations. That is low torque, and the machine will be run for short periods of time. Turning it up for hi rpm is a chance you will take. The motor may not live through it. The machine its self may be damaged in the process. Not to mention, is your chuck rated for the rpm?

VFDs are great for motor control, but use it properly. Use it right, most any 3-phase motor will get along with it.

A more powerfull motor wont hurt, not enough power, and you may wish you had a slightly bigger motor.

Good Luck with your project
 
CluelessNewB said:
I assume you are planning to use the VFD for speed control as well as to convert from single phase to 3 phase. You should really consider going to a sensorless vector drive rather than the volts/hertz FM50. For a little more money you can get a Teco JNEV. The 2 hp model JNEV-202-H1 is about $30 more than the equivalent FM50 and would be more appropriate for speed control on a lathe.
Click to expand...

Thanks Clueless for your response, can you expand on you points for the upgrade on the VFD. You say the its more appropriate please explain. Thanks
 
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