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Mazak 18x80 VFD drive conversion

Overland

Stainless
Joined
Nov 19, 2017
Location
Greenville, SC
I hope that someone can help here please.
In the process of converting a lathe I just bought to VFD drive. I want to use the existing "Forward/Stop/Reverse" handle to control the drive. This handle is set up to control the existing Forward/Reverse contactors, through limit switches, according to the circuit diagram.
So my question is: Where are these limit swithes located on the lathe ?
The Fuji drive I've bought (15 hp) has a diagram for an external switch for reversing. It seems to me that to use the existing handle and limit switches would be the best way to do this.
I've spent about 1/2 hour looking on the lathe but can't locate these switches.
Thanks in advance,
Bob
 
I'm not sure if we are aloud to talk about manual Mazak lathes in this part of the forum. But I just did this conversation on my similar vintage 21x100 Mazak.
 
Yes for sure. The switches are buried behind the feed gear box and would require complete disassembly to access.
Good news is you can find the wires that go to the switches on the terminal blocks in the electrical compartment under the feed gear box and easily make a connection there. Just follow the wires down from behind the feed gear box and confirm they are the right ones with an ohm meter. If you want I can look what the wire numbers are on my lathe. Not guaranteeing they will be the same.
Joe
 
Thanks Joe,
I did find the switches where you said. I can see the connections on the wiring diagram also, so this should be quite straight forward.
Thanks for your help
Bob
 
It was very straight forward

So I installed a Fuji 15 hp VFD / Inverter. (size the inverter for twice the power of the motor is a good rule of thumb).Wired it directly to the motor terminals, bypassing and leaving in place all the existing contactors, etc.
Then disconnected the forward/reverse limit swith wiring from the terminal block and connected these with light gauge wire to the control terminals on the inverter - very easy and straight forward.
I got a Dynamic Breaking module to match the inverter from Fuji. This allowed to program the decelleration rate.
Programming the inverter to use the remote lathe forward/reverse switch was easy - just change one input code.
Programming the soft start ramp speed also easy.
I programmed the decelleration to be quite aggressive, so it seems to stop in less than one revolution - almost an emergency stop.
So the whole job cost me about $750 including all the wiring, breakers, VFD and DB module. It works very well and the lathe operation is just like it was on the original 3 phase wiring.
Thanks for your help guys.
A friend has a rotary converter for his shop. The VFD solution was less expensive, quieter, I believe uses less power and gives some programming options for how the machine works, as discussed above.
Anybody wanting to use a 3-phase machine on single phase will find it very straight forward using a VFD.
Bob
 
Hello. New to this forum. Just setting up a recently purchased Mazak the same as yours. Would you be able to send me a copy of the wiring diagram? Someone messed with the wiring from the forward/reverse switch and I am trying to sort it out. Usually there is a diagram inside the door of the electrical compartment but there is nothing there. Your help would be greatly appreciated.
 








 
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