30k reliability

[charlesmann]

You’re right… I meant 30kW (see post 2). I have a 15kW so that’s what’s on my mind. Anyway… if you can go 3p motors you’ll be happier.

Happy or not, there isnt a 15hp 1ph and options are greater in the 3ph range.

Edit:
What does post 2 have to do with anything? If its how my “shop” is wired.
Already answered.

 

[Evvy Fesler]

Happy or not, there isnt a 15hp 1ph and options are greater in the 3ph range.

Edit:
What does post 2 have to do with anything? If its how my “shop” is wired.
Already answered.

Yes… post 2 was me replying to you. I understood 30kW. Just glitched when I replied tonight.

you can get single phase 15 HP motors and if all you have available is 240v single phase it’s the limitation with which you design. But if you can see your way to using the generator (or a rotary generator) to power your mill it’s a better solution.

Edit… I see where you said you would use 3p with VFD. Power it with the gen instead. Less complicated. Of course… you’ll need a supply of diesel fuel. Anyway… just some ideas. I have a relative who owns a finishing mill. I’m familiar with what you’re trying to do.

 

[87cr250r]

15hp 1phase motors are $6000. The same power in 3 phase is $1200.

I don't know about wood applications but single phase motors in metal working applications don't produce good surface finish because the shaft speed isn't constant over a revolution.

 

[Evvy Fesler]

15hp 1phase motors are $6000. The same power in 3 phase is $1200.

I don't know about wood applications but single phase motors in metal working applications don't produce good surface finish because the shaft speed isn't constant over a revolution.

Definitely produces a better finish. i missed that you were planning on 3p so my thoughts now are that you might consider eliminating that VFD and use the generator full time (if you get one). Are they reliable? Yes! They are “over built” for reasons we don’t need. Some complain about control circuits, but I am comfortable with them perhaps because of my electrical background. I don’t perceive the controls as complicated or difficult necessary. 30kVA is a lot of power. Controls are good. The engines are continuous duty and will run reliably, but… like any diesel they need a strong PM cycle.

BTW… I’ve seen many backwoods milling operations use a 3p motor as a rotary generator to make 3p from 1p. They buy them used for $200 +/- . This may be an option for a shoestring budget. Saves buying both generator and VFD.

 

[87cr250r]

You shouldn't direct on line start a 15 HP motor on a 30kW generator set. The generator won't be able to maintain the pull up voltage on the contactor which will cause it to chatter. This will burn out the contacts within a few starts. Regardless of motor phase you're still going to need a VFD or soft starter.

 

[Evvy Fesler]

You shouldn't direct on line start a 15 HP motor on a 30kW generator set. The generator won't be able to maintain the pull up voltage on the contactor which will cause it to chatter. This will burn out the contacts within a few starts. Regardless of motor phase you're still going to need a VFD or soft starter.

Yes, but… remember that this is a 3p setup. Start morors lowest to highest. Each one that starts and idles will supply generated current. People will often use a 3p motor connected to 1p as a generator. Get it started with a pull rope snd it will make electricity for the third leg. Basically, the 1p 240 going in “excites” the rotor and with a little help (pull rope) it spins. We now have a poor man’s generator to run the shop. If we reapply this theory to the OP use case, where a generator produces 3p, starting the lower HP motors first creates a surge supply system and the generator should chug along normally.

 

[charlesmann]

@Evvy iv only come across 1 15hp motor that is more likely to actually be single phase. https://www.mscdirect.com/product/details/89372825 $8,000, I'm sure it would SUCK the amps, vs. a 3ph, but no listing on amp draw.
the other 15hp motor is confusing bc it says 3ph in the title, but 1ph in the tech specs and i do not believe a 1ph 15hp motor would draw only 18 amps. https://vfds.com/galt-electric-odp-motor-gdp01504254tk-15hp-1800rpm-3-phase-208230460v-60hz-254t

i need the vfd to do its job, control the spd esp on the 1.5hp lift motor and vfd for maint,ts and tests on the 15hp main motor and i do not want, nor is it good on the drive belt or a 25 foot 1.5" wide wood cutting band to snap all 15hp and 1800rpm to the system.

as for the 30k being a lot of power, yes, it is, more than i need. but as iv also said, the other use for a generator is a back up hm gen for power outage. from all the research iv found when dropping from 3 phase to single phase, around 1/3 of the rated power output is not there. so a 15v would be a 10k, which isn't enough for power for full house usage. so, for mil gen sets, 30k is the next option, for civ sets, built or purchased complete, 21-24k should provide ample output, with a lil extra to spare.

i am aware i will need a supply of diesel fuel. i don't know how else i would power the gen head without an internal combustion engine, esp in an emergency power outage, be it gas, lpg, natural gas or diesel.
also, using a gen set will allow me to operate run electrical items away from any other elec power supply in remote location.

 

[charlesmann]

Yes, but… remember that this is a 3p setup. Start morors lowest to highest. Each one that starts and idles will supply generated current. People will often use a 3p motor connected to 1p as a generator. Get it started with a pull rope snd it will make electricity for the third leg. Basically, the 1p 240 going in “excites” the rotor and with a little help (pull rope) it spins. We now have a poor man’s generator to run the shop. If we reapply this theory to the OP use case, where a generator produces 3p, starting the lower HP motors first creates a surge supply system and the generator should chug along normally.

how would starting the 1.5hp (or 3/4 hp haven't decided yet) running through a 10:1 rgb to only lift/lower the sawhead help supply power to help start the larger motor? I also do NOT want the lift motor running full steam ahead, NOR do i want my main motor running full steam during initial start up, maint checks or troubleshooting, hence the need for VFDs to vary the speed at which the motors turn.
this is similar to what I'm building, but i am wanting to be mobile, as where the 1000 is stationary.

WM1000 Wide Slab Industrial Sawmill

#html-body [data-pb-style=QIWCG19]{justify-content:flex-start;display:flex;flex-direction:column;background-position:left top;background-size:cover;background-repeat:no-repeat;background-attachment:scroll} The WM1000 industrial sawmill is designed to saw large logs up to 67" wide.

woodmizer.com

 

[charlesmann]

15hp 1phase motors are $6000. The same power in 3 phase is $1200.

I don't know about wood applications but single phase motors in metal working applications don't produce good surface finish because the shaft speed isn't constant over a revolution.

From what iv researched on band/blade spd, there is an allowable varying fpm band speed.
Smaller cut width mills use single or three motors. The mill im waiting 11 months to take delivery of (lt 15 wide) has a 36” cut width and motor choices are 10hp 220v single phase, 220v 3 phase or 460v 3 phase.
Higher production portable mills (lt 50) with same cut width have a 25hp 230/460v 3 phase option as well as a diesel and gas burner.

 

[87cr250r]

Sizing a generator is fairly straightforward.

The nameplate rating needs exceed the sum of all of your loads.

AND

The nameplate rating must be at least double the largest motor rating for DOL starting.

Pick the largest of the two numbers.

However, with a VFD the generator nameplate and largest motor nameplate can be equal.

VFDs and motor contactors cost the same nowadays. It only makes sense to run the VFD. Even with double the motor power available, I still find contact life to be short due too chattering due to cheap voltage regulators used with the low power sets. I've had frequent contact failures on 15 HP air compressors driven by a 65kW generator set.

 

[charlesmann]

Sizing a generator is fairly straightforward.

The nameplate rating needs exceed the sum of all of your loads.

AND

The nameplate rating must be at least double the largest motor rating for DOL starting.

Pick the largest of the two numbers.

However, with a VFD the generator nameplate and largest motor nameplate can be equal.

VFDs and motor contactors cost the same nowadays. It only makes sense to run the VFD. Even with double the motor power available, I still find contact life to be short due too chattering due to cheap voltage regulators used with the low power sets. I've had frequent contact failures on 15 HP air compressors driven by a 65kW generator set.

total watt draw with all 3 motors (15hp, 5hp and 1.5hp if i go with the 1.5) is around 14kW. Im not sure what DOL means, but i think it means direct operating load, correct? if so, i am not finding anything on any of the websites for any of the motors I'm looking at for potential purchase for a DOL.
With the above info would you venture to say a 24kW gen set should provide enough 3 phase power

for the VFDs, depending price, for the 15hp motor, stay at the 15hp rating, but might step up to a 20hp if the price is right for a used one, in case i decide to upgrade to a 20hp later in the future. for the 1.5hp, a 2hp VFD, which will carry the load for either the the 3/4hp or 1.5hp, depending which motor i go with. reason for going with the 1.5hp motor, it will provide more tq than the 3/4hp mated to a 20:1 rgb, which will allow me to use a 10:1 or 15:1 rgb to allow for a faster total rotational speed for the lifting mechanism at full power input, then slow way down when coming up to the next cut when lowering.
money is always a factor, and i would like to go new for the fact you don't the condition of used items on eBay, craigslist or fb market place. but the finance manager (wife) will end up setting the amount of $$$ allocated for the purchase of stuff, or tell me to stay with my current set up and spend the $300 ish for an elec winch to have a sprocket machined to the dia. of the wire drum and weld it to the drum. I can do a LOT of r&d for $4000 to build up a generator, buy the motors, VFDs, electrical outlet/plugs, wiring and other misc things needed.

You say i need a voltage regulator. but a google search and search of websites I'm looking at for purchases of the motors and VFDs, i am not finding 3 phase voltage regulators. everything i find when i search voltage regulator, results pop up for dc voltage power supplies. could what you are calling a voltage regulator, have a different actual/technical name?

 

[Evvy Fesler]

how would starting the 1.5hp (or 3/4 hp haven't decided yet) running through a 10:1 rgb to only lift/lower the sawhead help supply power to help start the larger motor? I also do NOT want the lift motor running full steam ahead, NOR do i want my main motor running full steam during initial start up, maint checks or troubleshooting, hence the need for VFDs to vary the speed at which the motors turn.
this is similar to what I'm building, but i am wanting to be mobile, as where the 1000 is stationary.

WM1000 Wide Slab Industrial Sawmill

#html-body [data-pb-style=QIWCG19]{justify-content:flex-start;display:flex;flex-direction:column;background-position:left top;background-size:cover;background-repeat:no-repeat;background-attachment:scroll} The WM1000 industrial sawmill is designed to saw large logs up to 67" wide.

woodmizer.com

If each of the motors is connected to it’s own VFD, starting one won’t help with the others. In the scenario to which I replied, the member was warning about surge currents causing the contactor to chatter. He’s right about that. I was responding to a theoretical scenario where all motors were sourced to the generator without VFDs. It’s the nature of this forum to get sidetracked!

 

[87cr250r]

DOL is direct on line. That refers to starting a motor with a magnetic contactor or switch. A 15 horsepower electric motor is going to draw 60 horsepower during a DOL start. The overload duration is short so thermally the generator can handle it. But generator rotating assembly needs to have enough inertia to ride though the spike without dropping frequency and the voltage regulator needs to have the power to keep the field up. If your voltage drops below 80% or so during the start there won't be enough voltage to firmly hold the contacts together in the motor starter. In this case the contactor will chatter and burn out or worst case weld itself together in a single phased condition.

 

[charlesmann]

@87cr250r
So the DOL is null since my plans are to use 3ph and VFDs, correct?

I did find a 3ph power controller up to 24kw, regulating voltage. Is this what you are referring to as a voltage regulator?

3 Phase 4 Wires SCR Power Controller, 6/9/12/24kW

SCR power controller is a simple power regulator, can regulate voltage & power and control temperature. Rated power can select 6kW/9kW/12kW/24kW. Control signals are optional in 4-20mA, 0-5VDC, 0-10VDC. Rated voltage is 380VAC and input is 3-phase 4-wire. The SCR controller is small in size...

www.ato.com

A commercial sparky was suppose to have already come out by now, so im gonna give him a call in a final attempt to give him my $$ to hook the system up. But my first step is making sure i have what i need to do this properly and safely. Im 99.8% sure i could wire it up, but doing it safely, that could be a different story.

 

[charlesmann]

If each of the motors is connected to it’s own VFD, starting one won’t help with the others. In the scenario to which I replied, the member was warning about surge currents causing the contactor to chatter. He’s right about that. I was responding to a theoretical scenario where all motors were sourced to the generator without VFDs. It’s the nature of this forum to get sidetracked!

gotcha. replying to one post can get intermingled all to easy. but i am NOT eliminating any VFDs, and I'm guessing he was replying to your post of eliminating the VFDs and direct wiring the motors, which I will not or can not do. from my initial post, i stated using VFDs with a 3 phase generator setup. i currently have no plans of running any of this on single phase, using a phase converter to VFDs, which i could, but currently, there are no plans for it unless building a 3ph gen setup, motors, and so forth exceed the budget my finance officer just gave me.

I have heard of people taking motors and turning them into rotary phase converters, and phase converters are available, some way to dang expensive and some with a very reasonable price tag.
Id rather exhaust all efforts of building a gen set first, before looking into a phase converter, unless you are saying using, say a 20hp motor and reversing the leads, so to speak, and make the motor, a generator, still being powered by the diesel engine.

Id rather again, first exhaust my options and pricing of everything to build a proper gen set, before reverse engineering a motor to be a generator, unless its way cheaper, but if cheap means greater risk of damage and failure, id rather do it right the first time, or not do it at all and stay with the current set up i already have for powering my mill.

 

[87cr250r]

Automatic Voltage Regulator. It drives the field current on the generator.

This is an example of a cheap one. This one will have limited boost for starting big motors.

SE350 - Marathon

Shop for a SE350 AVR from Marathon. Order from General Power's large stock and industry-leading lead times which is weeks quicker than the competition.

www.genpowerusa.com

Here is an example of a more premium regulator.

AVC63-12, Voltage Regulator - Basler Electric

Enjoy proven, dependable, high performance with Basler Electric's AVC line.

www.basler.com

 

[Evvy Fesler]

gotcha. replying to one post can get intermingled all to easy. but i am NOT eliminating any VFDs, and I'm guessing he was replying to your post of eliminating the VFDs and direct wiring the motors, which I will not or can not do. from my initial post, i stated using VFDs with a 3 phase generator setup. i currently have no plans of running any of this on single phase, using a phase converter to VFDs, which i could, but currently, there are no plans for it unless building a 3ph gen setup, motors, and so forth exceed the budget my finance officer just gave me.

I have heard of people taking motors and turning them into rotary phase converters, and phase converters are available, some way to dang expensive and some with a very reasonable price tag.
Id rather exhaust all efforts of building a gen set first, before looking into a phase converter, unless you are saying using, say a 20hp motor and reversing the leads, so to speak, and make the motor, a generator, still being powered by the diesel engine.

Id rather again, first exhaust my options and pricing of everything to build a proper gen set, before reverse engineering a motor to be a generator, unless its way cheaper, but if cheap means greater risk of damage and failure, id rather do it right the first time, or not do it at all and stay with the current set up i already have for powering my mill.

Yeah… I’m sorry that I let the thread go astray on you. This is a fun loving group who like to help. After awhile you get used to the sidetracks and really, they’re helpful because they challenge us to think around a problem. One never knows where an, “awe-shucks, I wish I had thought if that,” comes from, but it’s delightful when it happens. (Forum rules, we can’t say awe shish kabob).

VFDs are in. Got it. This design constraint drives you down the path that you’re on. You knew that!

Digression… rotary phase converters are nothing more than a 3P motor with capacitors that are connected in a way that allows auto starting of the motor and some phase-to-phase balancing. A poor man’s implementation of that is to forgo the capacitors and use a pull rope wound around the shaft to start it. A lot of backwoods shops do this because they can only get single phase into the shop and used 3P motors are cheap. If you can stand to not operate during power outages this is a viable option.

Please allow me to ask an obvious question that, after getting to know you here, I’m sure you’ve thought of! Will your power company bring 3P to your shop?

Evvy-

 

[charlesmann]

Oh yea, the power company will bring it out, for a 6’ tall solid gold monkey.
Seriously though, no, not for 1 customer, even though there is 3 phase 4 miles to my west and high tension/voltage and sub station to my south.

Bringing me 3ph also ties my hands to where i have to set my mill up. It also doesnt help if power goes out, i still would like a back up generator for power outages.

 

[Guyfang]

None of you asked this question. What kind of 30 Kw do you want to use? MEP-004A? MEP-804A? MEP-804B? MEP-1050?

Well, there is some room for thought.

 

[charlesmann]

None of you asked this question. What kind of 30 Kw do you want to use? MEP-004A? MEP-804A? MEP-804B? MEP-1050?

Well, there is some room for thought.

I don't know the difference between them. you have any input?