Lathe motor won’t turn over on solar

[Chris42404]

You might see an improvement using an Easy Start device. They are pricy but very effective, it can lower surge current by as much as 70%.
I'm a very satisfied customer I can start & run a 15K RV AC unit on a EU2200Si Honda in ECO mode, with other minimal loads running.

I didn’t see your post until after I said the same thing. The Easy Start controllers are very handy items. I’ve played with several of them myself and they have never skipped a beat for me. A lathe as opposed to a compressor is kind of off of an off label application, but I bet it would work

 

[RCinFLA]

If the motor does have a centrifugal or other start capacitor dis-engage switch it should be bypassed with these softstarter/starter boost cap boxes. The softstarter/boost cap boxes takes over the dis-engage switch function.

For a motors with just a start capacitor and cutout switch, I would begin with same cap value in the softstarter. You might try increasing value by 50% to see if you get more improvement in startup surge current. Just do not want to get too high as there may be a small chance of damaging motor start windings. Optimum value would likely be 90 deg current phase shift on start winding relative to run winding current. That takes hall effect sensors with two channel scope to measure. You have to move some jumpers to clear previous profile training and start over training with factory initial settings if you want to play with different startup capacitor values. There is on-line docs on how to reset training.

I just put a EasyStart ASY-368 on my 4 ton central air cond with Copeland scroll compressor. Copeland scroll compressors are rugged but are notorious for high startup surge current.

As stock setup (240vac)
Startup surge = 203 amps for 400 msecs, run 14.1 amps.

With EasyStart 368
1st training startup surge = 102 amps
2nd training startup surge = 93 amp
3rd training startup surge = 84 amp
4th training startup surge = 73 amp
5th training startup surge = 64 amp (noticable startup 'grunting' )

Final auto-selected startup profile = 73 amps ( 64% reduction )

I probably could squeeze a little more out of it with a slightly larger value start capacitor. My inverter had no problem with the 73 amps.

The training is just running through various softstarter ramp profiles via Triac (voltage dimmer) control.

These boxes are a coordinated combination of softstarter and hardstart capacitor. A hard start cap kit is used when having start up problems with low AC line voltage. Alone, a hard start kit may increase startup surge current. A softstarter is just a voltage dimmer ramp up. They work well for three phase motor but for single phase motor they lower startup surge but extend the length of startup time so for an inverter, a softstarter alone usually does not help enough because the lower surge current lasts too long in time.

 

[softdown]

I did not muscle through the replies but had a similar problem when starting with solar in 2010. Assuming a robust 12-15 amp motor and the accompanying starting surge - you need several things:
A battery/batteries that can supply high surge current
Cabling that can supply high surge current. This may involve ~2/0 AWG Cu at 12 volts for example.
Very large inverter. I was using a lot of power tools building this shop. One of the first things I had to do was return an ~3000 watt inverter and get an ~5000 inverter. Inverter surge current is important. Memories are 10 years old - numbers could be off.

Using too small of inverter can damage your motors as well.

Then you have the soft start option a few mentioned.

Being a seasoned tool addict I buy a LOT of big, used tools made in America and Japan for nostalgia and practicality. A decent way to test the health of a large 12-15 amp motor is to plug it in. If it literally jumps into action with the ON button, that is a good start. But it could also have a soft start motor. I suspect Makita employs that at times.

 

[eprotiva]

power factor, you need some ntc resistors inline to eat the inrush.

 

[Zil]

Sunburnt solved the problem in Apr 9, 2020. Has not been back. Maybe lose clothing caught in the lathe that now turned.

 

[Hdonly]

I assume it is a capacitor start motor. Possibly your start capacitor is failing.

 

[8_Hz_WAN_IP]

I have a hobbyist lathe with a single-phase 115v motor of 3/4 HP. This motor turns on normally when I am connected to grid power, and VERY occasionally when connected to solar. But most of the time on solar the motor does not spin up. I’m wondering what I can do to allow it to start on solar.

My solar system, when running on batteries alone, can produce at least 70 amps output for several minutes at least (I have tested this with an electric heater and the battery monitor shows 70 amps coming out of the batteries when the heater is on). I wouldn’t think the 3/4 HP lathe motor would take anything like that for startup amperage, but perhaps it is possible.

Could adding some additional start capacitors to the motor cicuit help in this situation?

It seems to me that your equipment requires a surge in startup current that exceeds the output of your batteries. Parallel supercaps could remedy this, or a higher current output battery bank (i.e. adding more batteries in parallel). IMHO