Thread: Some advice please

Hi Mike,
I'm confused as to exactly what you are doing.
Is the output of the VSD connected directly to the motor?
Are you trying to use the factory lathe switches to contorl the VSD?
Pictures?


Stuart

Happy Birthday!

I am far from an expert on VFD's but i thought you should never have a switch between the VFD and motor, you have to use the VFD as the switch/reverse etc

You do not use the original switch gear when installing a VFD... You can use your original switches, but they will have to be wired into the control ports on the VFD..

If your lathe was 415V before has the motor been rewired from delta to star to run off 240V

You can only run one motor per VFD..

Just a guess but if it is anything like my Triumph then it will have a stepdown transformer to reduce the normal 415 volts (I assume it is a 3 phase machine) down to 110 or 24 volts AC (or whatever) is required to operate the coils in the contactors. There are two contactors in my Triumph, one for the motor and one for the suds pump. If you put 220 volts into a stepdown transformer which is meant to reduce 415 down to 24 volts then it sounds about right that you are getting 9 volts.

You can get around this problem by rewiring the control box with the appropriate 240 to 24 volt stepdown transformer to suit the 24 volt AC coils on the contactors.

This is not a job for the novice and if you do not fully understand what is going on I highly recommend that you employ someone who does. The voltages in these control boxes are potentially lethal.

Ah bugger, I feel damn dull.

I am trying to run the wires from the lathes origional power cord into the VFD then hoping all the switches will work...

So, all I need to do is wire the VFD direct to the motor and use the VFD as my new 'control box'?

Damn, so obvious........ ( give myself a hard upper cut)

Thanks fellers,

Mike

Originally Posted by mike rolly

So, all I need to do is wire the VFD direct to the motor and use the VFD as my new 'control box'?

Assuming there arent some functions of the factory wiring that you would like to keep, like Fwd/Stop/Rev on the carriage?

Stuart

Just to qualify my last post I have absolutely no experience with VFD's but I did originally run my Colchester Triumph off a massive single phase Weg 7.5 hp motor, before I bit the bullet and had 3 phase installed. Consequently I changed the transformer in the control box to a 240 - 24 volt and when I converted the Triumph back to 415 volt I picked up the neutral in the 3 phase plug.

I would be interested to have a play with one of these VFD's, I reckon you could keep the original switchgear if you change the stepdown transformer and have the VFD between the motor and the control box.

Carriage is all controlled by gearing Stu, once the motor works, the gears should turn and all be well.

Gerbilsquasher, I will have a look at your idea when I have some daylight tomorrow mate. These little magic boxes known as VFD's are bloody impressive. There are over 100 different parameters you can set and hook in a potentiometer for variable speed at the turn of a dial. Amazing technology and very inexpensive for what they do.

I can see some great bargains to be had at auctions and the like on some 3 phase kit that sell for next to nothing as not many people want manual, 3 phase machines. Got my eye out for a surface grinder now.

Once I get it all squared away I will get some pics up, including my flash new slab I put in last weekend for the lathe.

Mike

Originally Posted by mike rolly

I can see some great bargains to be had at auctions and the like on some 3 phase kit that sell for next to nothing as not many people want manual, 3 phase machines. Got my eye out for a surface grinder now.


Mike

Ha! I have already been lulled into the 3-phase machine bargain bonanza and now have the opposite problem- all this gear that I have to make work on 'two' phase, because I am stupid enough to want a bigger shed. Rather than rewire/remotor/VFD 10 different machines I am going to build a phase converter. Making 3 phase from 480 volts is not as hard as making it from 240. I am definitely not going to drain the grid like the Griswold house in National Lampoon's Christmas Vacation

Originally Posted by Gerbilsquasher

Ha! I have already been lulled into the 3-phase machine bargain bonanza and now have the opposite problem- all this gear that I have to make work on 'two' phase, because I am stupid enough to want a bigger shed. Rather than rewire/remotor/VFD 10 different machines I am going to build a phase converter. Making 3 phase from 480 volts is not as hard as making it from 240. I am definitely not going to drain the grid like the Griswold house in National Lampoon's Christmas Vacation

10 machines!!

Your power line will glow when you are running flat chat mate

It is a hobby, so should still fly under the Carbon Tax radar