Thread: Hercus motors

Cant really comment on the motor but not really sure how useful it would be for the Lathe.

I would of thought it would be better suited to some type of Direct drive application.

If the Speed control could be relocated off the motor it could be more useful in this application.

Hi, you can purchase a replacement single phase motor from here

Australian Metalworking Hobbyist

He restores and sells parts for the hercus lathes, and stocks both a 1/2 HP and 1HP motor both of which should be a straight swap (but double check this with him)

I think he is also a registered member on the forums here.

Originally Posted by Ch4iS

Hi, you can purchase a replacement single phase motor from here

Australian Metalworking Hobbyist

He restores and sells parts for the hercus lathes, and stocks both a 1/2 HP and 1HP motor both of which should be a straight swap (but double check this with him)

I think he is also a registered member on the forums here.

Wow - that's excellent info - thanks.

Originally Posted by pipeclay

Cant really comment on the motor but not really sure how useful it would be for the Lathe.

I would of thought it would be better suited to some type of Direct drive application.

What do you mean by this?

If the Speed control could be relocated off the motor it could be more useful in this application.

I agree.

That comment was made refering to where the controller was located,somewhere easily reached.

The other thing to consider would be the available torque through its speed range.

I'd suggest not wasting your money on swapping the motor with a single phase bodge. You will be infinitely happier in the long-run if you fit a VFD to your existing motor. If the motor is not currently capable of being wired in delta configuration it is an extremely simple job for a motor rewinder to convert the motor. I have 3 VFDs in my machines and converted all the motors myself, I've got it down to about 30 minutes now

Do a search here for VFDs, there's a lot of information available. It may not be as cheap as swapping a motor, but gives you an enormous number of benefits; soft start, soft stop, infinitely variable speed, reverse, emergency stop, etc etc etc. Small VFDs can be found on ebay for realistic prices, and you only need one the same size as your motor, ie you don't "upsize" it. Many people think of them as 3 phase converters but this can lead to wrong conclusions. They are actually motor controllers, some of which just happen to convert single phase to 3 phase.

Pete

Edit: Holy Crap! I hadn't looked at the motor you were considering until after I posted. If you're even considering dropping 650 big ones on converting to a single phase, then definitely go down the VFD path! You will get more benefits for well under half the price, and that's assuming you have a rewinder convert to delta for about 60 bucks!

Originally Posted by Pete F

Edit: Holy Crap! I hadn't looked at the motor you were considering until after I posted. If you're even considering dropping 650 big ones on converting to a single phase, then definitely go down the VFD path! You will get more benefits for well under half the price, and that's assuming you have a rewinder convert to delta for about 60 bucks!

Thanks Pete.

> While hunting around for single phase motors I stumbled across what looks like a nicely
> made Aussie 1 HP variable speed single phase motor.

Bob, firstly I am not sure that motor is Aussie made. Yes sure, CMG is an Aussie company. But I bought a new blue 1HP CMG 3-phase motor 5 years ago for the drill press, and it's nameplate says "CMG Australia", and NOT "made in Australia". And the owner of the motor shop I bought it from told me it is indeed made in China - he must know because he also rewinds motors, and motors is all he does.

Second, that motor you are looking at is most likely a 3-phase motor with a built-in very basic and simplified VFD, without any bells and whistes, and most probably not of the better "sensorless vector" type. Meaning it probably only covers a 1:4 speed range with reasonably useful torque. You hook it up single phase, that is why they call it single phase. These are often used for fans and pumps. I would say if you do not want to fiddle around with electrics and want something to plugin and forget, and price does not matter, then go for it. I just feel $600 is a bit steep.

For $600 you can buy separate single phase input VFD and 3-phase motor, and get some change to buy some tools. 3-phase are the cheapest and simplest to make motors there are. The downside is you have to wire it all up yourself, and you have to study the VFD manual, and you have to decide if you want a 2 or 4 or 6 pole motor etc etc. One thing I can guarantee though, if you convert your lathe to VFD variable speed of whatevery make, you will never look back.

Chris

Here is the link to more info about this variable speed motor from Hare&Forbes. It is indeed an inbuilt VFD. To me this means if something fails you toss it as a whole, motor and VFD.

http://www.transaus.com.au/files/TA_...Master_CMG.pdf

Note they only specify a 1:3 speed range, not good enough for a lathe. Maybe 25 years ago it would have been a great thing. For a lathe you want a VFD that can work from standstill upwards. Otherwise you still change belts all the time, and you still cannot do the very low speed tasks.

By the way, CMG call this drive "Speedmaster". That is the same name the US Leeson company gives their VFD's. It could be it is simply a Leeson single board VFD built into a GMG motor? Chris

Thanks cba, I'm definitely going with a VSD. I just need to get the go ahead from the PLC techo at work who deals with these things on a regular basis to see if he can give me a hand to install it. I could just go ahead and have a go myself but if he helps me then I have a built in skilled enthusiastic support thereafter.