VFD On Geared Head Lathe

My friend Duane stopped over once again this morning armed with a bag of test devises and other tools of the trade. He solved the problem but we're still kind of confused as to why the machine was set up the way it was. Basically the whole control panel was set up to run on low voltage but the motors were wired for high voltage. The reason I couldn't get it to run on 220v after changing the motor over to low voltage was because the voltage at start up when fed from my 5hp rpc was too low for the transformers in the control panel. It caused the relays to chatter and drop out. Duane once again wired a 110v extension cord to the control panel to power everything except the motor starters and motor which were powered by the rpc. That allowed the relays to hold and the motor ran perfectly. I still can't run in high speeds but only because I don't have enough power to do it. If I had a 10hp rpc I'm pretty sure it would do everything it's supposed to do. For now I'm going to mount a seperate box for a 110v circuit to power the controls and use the rpc I have to run the motor. Duane seems to believe that now that he understands what was going on he could probably power it with his 7 1/2 hp vfd and get it to run in high gear. Now all I have to do is decide where I'm going to put the machine, finish wiring it, and get it leveled up so I can take some true test cuts with it. Thanks for all the help.

Chuck
 
Congratulations on finding the problem with the drive motor on your lathe. You done did it my man. Stayed with the problem until it was resolved.

I too was puzzled about your remarks about the contactors clicking then everything coming to a halt. It did not dawn on me at the time that it was due to voltage drop on start-up. Makes sense though if you are hurting for size on the power supply.

You will need to consult a heater chart to see if the B22 heaters are correct for your application at 240 volts. I don't know what the B1.03 units supply but they need to be verified also.

My experience with RPC's is limited and the few I have seen never impressed me. I do not care how fancy the label is or how professional the construction, it is still just Hokus Pokus Brewhaha for the real meal deal and the alternate choices are many.

Again, CONGRATULATIONS! Your "JUNIOR ELECTRICIAN" card is on it's way! You have earned it.
 
"Again, CONGRATULATIONS! Your "JUNIOR ELECTRICIAN" card is on it's way! You have earned it."


I think you better hold off on the JE card. All I did was observe Duane while he did all the troubleshooting. I did learn a few things
while watching him though. The first thing he did when he first opened the control panel was check the number on the heaters to see what they were rated for. They are the correct heaters. Again, that's what confused us. Everything in the machine was set up for low voltage but the motors were wired for high voltage. I guess it shouldn't surprise me. I have seen "fixes" done on used machines that just make you ask yourself, "what was he thinking?".

Chuck
 
Good going, Chuck -to you and your friend.

I'm sorry I couldn't help much but, as soon as you mentioned heaters etc, it was out of my immediate realm of knowledge...


Ray
 
Just a note for those of you about the heaters, if you did not have to push the reset buttons, not an overload or heater problem. just for future reference.
 
Heaters are definitely not going to be an issue now. I am the proud owner of a Mitsubishi 7 1/2 hp constant torque vfd. I moved the lathe to it's permanent location and leveled it today. I was in the process of setting it up for a test cut to get the tailstock dialed in when Duane showed up. He did a temporary hook up to test the vfd and for the first time I got to see the lathe work in all speeds. I removed the chuck from the spindle before going 2500. I want to research a little and find out what speed it's rated for before I turn it that fast. We did a little horse trading and I own the vfd which he's going to wire up for me. It should be pretty straight forward except for the spindle brake. He has some ideas for that, but his explanation was kind of going over my head. Anyway....all I have to do is the no brain mounting work and he's going to take care of all the wiring and switches. Life is good!

Chuck
 
Chuck K said:
Heaters are definitely not going to be an issue now. I am the proud owner of a Mitsubishi 7 1/2 hp constant torque vfd. I moved the lathe to it's permanent location and leveled it today. I was in the process of setting it up for a test cut to get the tailstock dialed in when Duane showed up. He did a temporary hook up to test the vfd and for the first time I got to see the lathe work in all speeds. I removed the chuck from the spindle before going 2500. I want to research a little and find out what speed it's rated for before I turn it that fast. We did a little horse trading and I own the vfd which he's going to wire up for me. It should be pretty straight forward except for the spindle brake. He has some ideas for that, but his explanation was kind of going over my head. Anyway....all I have to do is the no brain mounting work and he's going to take care of all the wiring and switches. Life is good!

Chuck
Click to expand...

Congrats! Its always nice to see the machine working as it should.

What is the model number on the drive? I work with Mitsubishi drives all the time. Constant torque drives are usually used to drive fans, not so great for machine tools. Will probably work just fine though.

-Cody
 
Hmmmmmmmmmm.....I was under the impression that constant torque vfds were used for things like conveyors where you needed the same torque at all speeds. Maybe I should research this a little.

Chuck

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Codered741 said:
Congrats! Its always nice to see the machine working as it should.

What is the model number on the drive? I work with Mitsubishi drives all the time. Constant torque drives are usually used to drive fans, not so great for machine tools. Will probably work just fine though.

-Cody
Click to expand...


Cody, After googling the term "constant torque vfd" I have to believe that you have your info wrong. Fans are usually run with variable torque vfds.

Chuck
 
Chuck K said:
Hmmmmmmmmmm.....I was under the impression that constant torque vfds were used for things like conveyors where you needed the same torque at all speeds. Maybe I should research this a little.

Chuck
Click to expand...

Hey Chuck,

Please disregard what I just said. Eyes saw constant, brain said variable. Never mind. Evidently I need either more coffee or more sleep...

Sorry. Constant torque drives ARE what you want for machine tools, Variable torque drives are for fans, etc.

I would still like to know the model number if you have it handy.

-Cody
 
I'll have to get it for you tomorrow. It was 200...but there was a letter in the model number that I don't remember right off hand. It's an older model but it's never been used. It's a lot bigger than the ones I've had in the past. Must be close to 12" tall. I'm assuming that with the newer technology they have shrunk things down a lot. I'm sure it will do everything I need it to do.

Chuck
 
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