3/4 vs 1 hp for SB heavy 10

[Santorini352]

Hello everyone.

I am making progress on my heavy 10 but have been a lousy forum member by not communicating and posting pictures. Presently I am waiting on a dial indicator to evaluate spindle shimming. Leveling feet have arrived from McMaster Carr. When I started this project about 5 years ago I bought a new 3/4 hp GE motor and an Automation GS1 AC drive.

After watching many VFD videos I think I will buy the LENZE AC Tech SMV Vector and use the GS1 on something else. My reason is that the GS1 defies my ability to understand it's programming and would require a box enclosure. The Lenze SMV does not require a box and has sealed control buttons & housing. There are videos explaining the exact programming I would use.

The reason for this post is that as I try to digest information I wonder if I should buy a 1 HP motor instead of using the 3/4 hp motor. Although that may be overkill for myself I'm certain that my son and possibly grandson will want the lathe unless I've been putting lipstick on a pig.
IF I buy a 1hp motor I would probably buy it from the same place as the SMV Vector and try to convince them to configure the VFD/motor for me. It is unlikely that they would do it I will ask.

While I'm posting, what is an ideal tool post for my lathe?
That purchase will have to wait until my credit card cools off but I'm trying to think ahead.

Thanks in advance for any suggestions or comments (good or bad).

Stephen

 

[Ulma Doctor]

i don't think 1hp is too much overkill with rubber belting
if you have leather belting, it won't matter. 3/4 hp is more than enough power
the belt would slip before all 3/4 horses could be developed

 

[SLK001]

Are you talking about three phase motors? I don't think that you can run a single phase off a VFD. For a 10L, I would go with either a 1 or 1-1/2HP motor.

As for tool post, an AXA model QCTP works for 10" lathes. You can pick up a Phase II QCTP with holders for around $200.

 

[MrWhoopee]

I have an AXA toolpost on my Heavy 10, it is the right size. I am seriously considering replacing the 1 hp motor with a 1-1/2 or 2 if I can find one on a 184 frame.

 

[mksj]

The major advantage of going with a larger Hp motor is speed range, you loose Hp in a linear fashion below 60Hz and also the mechanical advantage. So there is some benefit over-sizing the motor, but there are limitations as to the the drive system, bearings and rigidity that limit a reasonable motor size. I think either a 1 or 1.5 Hp would be more than adequate, but if you have the 3/4hp and the GS1 why not give that a try first. The GS1 could go in the lathe cabinet if you have one, also seen them mounted to the door and swing out. If you do not know the programming parameters, I can put together a list of recommended parameters for that VFD, would need to get some more information on the lathe, motor specs. and wiring. You can PM me if you need some assistance. GS1 is discontinued, but was a popular VFD in its time. A word of caution, VFD's that sit unpowered for more than a year will have deterioration of their electrolytic buss capacitors and they are prone to failure on power-up. So when first powering up the VFD, some people recommend bringing up the voltage slowly (say with a variac), or powering it up for say an hour without operating the output.

In a 2 Hp motor a 6 pole, 1200 RPM motor would be a 184 frame, but that is a beast of a motor, couldn't see it on a smaller lathe.