Power issues.

[Redneck7]

Hey everyone,

I have very horrible power service at my property. I have a 7000 whisper watt diesel generator that I thought could use on my lathe.

The other night I plugged it in and the power light came on but the lathe would turn on and spin. So now I've been down tons of rabbit holes reading about start up power etc. I'm starting to think my generator won't work for this task. I'm still going to check a few things, like fuses, breakers and what not.

I'm not an electrician so lots of this is a 3rd language to me. I have a decent understanding but I'm wondering if wired the lathe for 120, if my generator would work then. It's currently wired for 220, I can't remember the size of the motor. For the generator 220 plug in is rated for 240 with 25amp. The 120 side is 120 with 25amp.

My question is would the start up draw be lower if I had it wired for 120?

I added some pictures so maybe someone with more knowledge can maybe find an issue. I'm thinking, I'm missing something.

Thanks everyone.

 

[djberta]

Your lathe will start better at 220. Your basically hitting the wall for your inrush on the electric motor vs your generator. At 7kw you should be good for 30amps. The problem is your gen can't keep up with the current to start the motor. Stalled or start rotor current can be as high as 6 to 10 times fla. You can alleviate some of this with a soft start. The single phase soft starts are used a lot for RV air conditioners. So they are out there and available. The other option is to replace the motor with a 3 phase one and go with a vfd.

Start and Stall protection of Induction Motor

When a motor is started, it draws a current well in excess of full load rating throughout the period that the motor takes to run-up to speed. While the motor

electricalsphere.com

 

[Bandit]

Hi, will try to help as can. Please note I am not an electrician. Some others knowing more then myself will likely be a long soon. It would be nice to have picture of the lathe motor name plate. On there is generally the amps needed to run at each voltage and the phase of the motor. And some other important things. The panel cover maybe for the lathe, see later, below.
Some basics, a motor is generally rated by horse power and or watts/kilowatts. A 1 horsepower motor on 120volts may use X amps to run, a 220/240 volt motor of 1 horsepower, will use 1/2 the amps to do the same thing. So by rewiring to run 120 volts you will draw 2X the amps
Another thing is that start up amps being used by a motor to start can be much higher then "normal" operating mode.
You have a picture of a panel cover and a name plate/ sticker on it and then the cover open showing wiring, maybe a transformer, 3 blocks, mag switches? and ?
The sticker/plate is a bit hard to read, appears to be, 1.5 kw ( motor size/hp), 110/220 volt, 10/20 amp, 60 hz, ( could be 50hz), and I think 1PH, (single phase).
I think this panel maybe on the lathe, as also has SHUGHSUNG??MACHINE TOOL WORKS on it.
If any of the above is wrong, please correct.
Also by using 110 volts from the generator, possibly/likely none of the mag switches will work and may need to be rewired or changed out. Checking for loose, broken wires, blown fuses, is never a waste of trouble shooting time.
As there are some troubles with photos on the forum at this time and I can not open them, only enlarge them on my phone and the pictures lose detail when that is done.
There are some very good electrical trouble shooters on this forum.
Does the generator have a power switch to switch from 110 volts to240 volts, I have seen a few that do. You get one or the other.

 

[slow-poke]

240V * 25A = 6000W
Quite common for generator manufacturers to advertise short duration 'peak' power, so decent chance that's what the 7000W advertised power rating is.

As mentioned image of motor name plate will give some insight.

Even a small say 1HP motor will pull about 25A during start up.

 

[djberta]

240V * 25A = 6000W
Quite common for generator manufacturers to advertise short duration 'peak' power, so decent chance that's what the 7000W advertised power rating is.

As mentioned image of motor name plate will give some insight.

Even a small say 1HP motor will pull about 25A during start up.

Sadly this is a real issue with big box store generators. I worked for about 20 years in the mobile equipment industry, drilling mostly. It is a constant issue with clients for rental equipment. They rent a 40hp generator to run a 40hp electric motor. Some of this is due to sales and rental staff not knowing what they are really talking about. They need the sale or rental and most people are not going to rent a 250hp generator to run their 40hp pump motor. You would need that at least to start that 40hp motor, more so if it was a hydraulic pump or the motor has to start a large load.

Redneck 7 is there a specific reason you want to run the lathe on the generator? Other then a bad service? if it is a bad service your likely better to look at a service upgrade or at the very least have the service repaired. In my early career I did just that many times on farms and acreages. Over time all connections break down, some more so then others. These connections can corrode and you will see volt drops and loss of power from them. One case from the utility pole to the house to their pump shack on a farm they lost 40 volts. When the pump motor came on it would dim the lights in the house. Code says it can not be more the 3% for a service and no more then 5% for a branch circuit.. Over head lines need attention when they have issues. Here in Alberta you can ask your authority to look at your power and to see if there is any repair needed. Atco, Fortus and others can come out and have a look at your power, you can call the service line. They are in charge of keeping the lines to your property area in good working order. They will usually come out in a day or two, they take this issue seriously. We all pay a monthly fee for this up keep. From the service providers pole or the other side of the meter if it is underground is up to you. It is your responsibility but a good electrician should be able to figure out and repair any issues you have.

 

[mbond]

In general, lights dimming when turning a motor on is caused by the inductance / capacitance balance going out of balance and leading to a large rise in impedance - the effective resistance in AC circuits.

In general, you want to run your AC motor at the highest voltage that you can. There are practical limits, but lower voltages require larger currents for the same power, and the loss is mostly related to current - theoretically I^2R

Usually, bad service from a utility comes in the form of non-sinusoidal voltage. If the peek voltage is simply lower, it is usually okay, but bad wave forms seriously mess with available power, rotation speed etc.

It is hard to say more without knowing more, but at least your 7KW generator won't deliver that power instantly, which makes inrush current a problem, and probably has a power factor of something like .75.

 

[Redneck7]

Thanks guys for all the replies, I'm gonna have to look into the 3 phase motor possibility.

For the question about why I want to use the generator. My property only has a 65amp panel and its filled up. Maxed out and lights already dim when I use a circular saw, and have lots of lights on in the house. Also my panel is not to code, and it does need to get moved. Its just not on the radar at the moment. I already had the generator from when my dad passed, I just assumed being a whisper watt, it would work. the lathe is in a building far away from the power and down in the trees. For the cost to update my panel and move it, then trench new power down to the barn, I could build a new garage and then put the right power in there for the cabin and the garage. (that more on the radar than anything)

I'm gonna have to talk with some friends that are electricians and see what some options are.

 

[DPittman]

For the cost to update my panel and move it, then trench new power down to the barn, I could build a new garage and then put the right power in there for the cabin and the garage.

There you go! That's all you need to do! Just spend money. With a great open mind like that you are really "wired" right for any metal working hobby. And if you are not of that persuasion already then this is the forum to be on. We will convince you that you "need" to spend some money somewhere.
And while there are obviously a big range of members budgets on this forum, I think everyone understands and respects limits. So don't think you need to avoid us or go bankrupt either. Even the rich have limits and priorities.

 

[quitereal]

Gas engine pulleyed to lathe, done.

 

[Tom O]

4th gear!

 

[djberta]

Thanks guys for all the replies, I'm gonna have to look into the 3 phase motor possibility.

For the question about why I want to use the generator. My property only has a 65amp panel and its filled up. Maxed out and lights already dim when I use a circular saw, and have lots of lights on in the house. Also my panel is not to code, and it does need to get moved. Its just not on the radar at the moment. I already had the generator from when my dad passed, I just assumed being a whisper watt, it would work. the lathe is in a building far away from the power and down in the trees. For the cost to update my panel and move it, then trench new power down to the barn, I could build a new garage and then put the right power in there for the cabin and the garage. (that more on the radar than anything)

I'm gonna have to talk with some friends that are electricians and see what some options are.

Interesting. I feel for the lack of power. Have a look at some of the old ideas on making capacitors to start motors. Think 1950's magazine stuff. You can make a small capacitor bank. This bank will provide some capacity for starting. Make sure they are in a metal enclosure. I'm trying to find a page on making them.

 

[BaitMaster]

Most farm service whole upgrades doing it legal and trenching underground are under 10k….. maybe 15 if you do 200A. All that assuming you don’t have more then a 100m run from the pole to the panel.

All bets are off if you go 3ph or bigger then 100a.

There are numerous ways to save money during that process too.

A panel/main service change out on a standard house in town is almost always under 5.

The things that can screw you is if the people before you didn’t get their permits and you are in town. The bill might go to 10k if they make you arc fault everything.

I don’t know what exactly your situation is but those are common numbers that I’ve seen. But hey, I’m also a random guy off the internets so take it for what it’s worth.

 

[Redneck7]

Yes my cabin only has 65amp service and my power panel is behind kitchen cabinets. The previous owner when they renovated, they never moved the panel... its just frustrating. my one yard light kicks off when the fridge turns on in the night.

I looked into both routes, 3 phase motor and a soft start. Both reasonable, but I remembered I met a business owner at a long range rifle course. He rebuilds Electric motors for refineries, so I'm gonna pick his brain and if he has the time, to come out and install whatever the best option is. I'm thinking its the soft start route considering how simple it seems.

 

[djberta]

Is your service overhead or under ground? Do you have a pole disconnect? I would for sure contact your service provider and have them come out and test your lines. They should do it for free. Once they have done that it verifies that the issue is at your cabin. It would suck to pay someone to come out and look at your stuff to find out that the utility had a problem 100m down the road from your place. What your describing is typical of a burnt or corroded system. Usually the neutral or what we now call the identified conductor has likely deteriorated over time. This issue expands beyond your lathe. This is a hazardous issue and needs to be corrected. Make a visual inspection of your outside wiring. If the panel is in an odd place this complicates things but it is not a huge issue. Do not be afraid to spend the money needed to fix this. It can be as easy as having an electrician come out, clean and make new connections. You do not need a new installation or upgrade unless you choose to do so. The system just needs to be repaired and brought in to working order.

PM me and I can go over it in more detail.

 

[BaitMaster]

Ya, when the guy before you hacks things together improperly, the bill is always significantly higher. That’s unfortunate.

On another note, your yard light should NEVER turn off when your fridge kicks on, so there is surely some unknown problem with your electrical system or service that should be rectified.

My instincts want to say it’s a connection somewhere or a small chunk of almost totally bad conductor.

A competent electrician should be able to find your issue and get it fixed for you. 65A service should be able to start a 2hp motor no problem.

I have a 30a breaker feeding my garage where all the action happens and I am not worried about it at all.

If you were drawing wayyy too much, your breaker would trip after 10 or so seconds and your motor would hum and buzz like a son of a.

That fact that that isn’t happening is a problem.

Even with excessive voltage drop, assuming the conductors are somewhat undersized, 240v motors are almost always rated to run on 208v 1ph. Which can go down to 200. Which is like 20% voltage drop off of nominal 240v.

The fact you aren’t blowing a breaker and are having strange flickering issues indicates a problem that should be fixable.

If your line is overhead, one of the splices is probably bad. If the line is underground, a chunk of the aluminum conductor is probably rotten.

A good electrician will have locators to find underground breaks and a bucket truck to re do overhead splices.

(I looked right above me, and @djberta has this licked.)

 

[Bandit]

A programmable soft start can make a massive difference, they might all be programmable, I don't know.
We had a 50hp motor on a booster fire pump that to be able to run on line power or from the backup generator. Line power was O.K., the generator was a "bit" small, put the soft start in. Could program ramping up to speed times, amp draw ramp up, and a number of other things. The genny could do the job and the fire hydrants did not try to jump in the air when the pump started boosting.
That soft start seemed to have as much programmable stuff as a decent VFD, maybe kind of one and the same don't know.

 

[mbond]

Yes my cabin only has 65amp service and my power panel is behind kitchen cabinets. The previous owner when they renovated, they never moved the panel... its just frustrating. my one yard light kicks off when the fridge turns on in the night.

I looked into both routes, 3 phase motor and a soft start. Both reasonable, but I remembered I met a business owner at a long range rifle course. He rebuilds Electric motors for refineries, so I'm gonna pick his brain and if he has the time, to come out and install whatever the best option is. I'm thinking its the soft start route considering how simple it seems.

do you really have a light that goes out? Or does it just dim a lot and then come back? If it is only 1 light, then I'd start by checking what bulb you have in that one.

probably your service has 208 or 240 single phase delivered and a ground rod somewhere near the pole to give you neutral for 120.

If there are corroded wires, it can be a big safety issue

There isn't anything magic about running a lathe using an electric motor, so if you don't have power, but you do have some other engine (old lawn mower maybe?) that could be a good choice

 

[Redneck7]

do you really have a light that goes out? Or does it just dim a lot and then come back? If it is only 1 light, then I'd start by checking what bulb you have in that one.

probably your service has 208 or 240 single phase delivered and a ground rod somewhere near the pole to give you neutral for 120.

If there are corroded wires, it can be a big safety issue

There isn't anything magic about running a lathe using an electric motor, so if you don't have power, but you do have some other engine (old lawn mower maybe?) that could be a good choice

My other yard lights I replaced to led when those big bulbs burnt out and are either costly or hard to find.

I was waiting for this last one to burn out to swap with an led but now that I turned it off, that won't happen. So I just need to swap it out.

 

[Redneck7]

Update. Here's a picture of the motor plate.

Rob said it would be best to get a 3 phase motor and vfd. He said he has a vfd he can give me for free from the shop. He also said the soft start I found online icm870 probably won't work. I sent him dimensions of where my motor is and he's gonna find me a 3 phase that will fit in that spot.

 

[slow-poke]

So run current is ~10A @240V
Rule of thumb for starting current is 4 to 8 times for several seconds, while the motor gets up to speed. So 40-80A, not a surprise the 25A generator is not up to the task.