Cook's Sharpener vs 2000w generator

[hersnsh#590]

This may be a little lengthy, but I hope there will be some value in it.

I recently purchased a new Cook's sharpener, and am happy with it so far.  My issue is that I'm trying to run the sharpener off a Honda EU200i generator, which gives about 1600 Watts of continuous power.  The sharpener has a 1/2hp motor, which takes about 400 w to run.  I've heard to start an electric motor, it can take up to 3 time the power that it takes to run the motor, so 400W X 3=1200w to start.   Well, the grind motor starts, and seems to spool up to proper rpm, then pops the breaker, even with the power cord hooked directly to the generator.  I have used the sharpener with Utility power with no problem, so I'm making the assumption the generator is the problem, not the sharpener.

My next step is to use a 5000w generator (4000w continuous) of all 120 v current to see if that corrects the problem, and I expect it will.  That 5000w generator cannot be permanently located at my mill location, as it is dedicated to the emergency power source at my house.  If the 5000w generator works, I may well buy a Companion 2000W Honda to run in parallel with the current 2000W and produce about 25 amps of power for the sharpener.  The only time I would need both generators running would be for sharpening.  Either would provide enough power to run the lights and O/H fan in the "sharpening room" or eventual LED lights for the TK 1600 mill for night operations. I'd like to keep the sharpener in close proximity to the mill, otherwise I'd relocate it to a conventional power source, and running Utility power to the mill would be more expense that I want right now.

I want to emphasize again, none of this epistle is intended as criticism of or dissatisfaction with the Cook Sharpener.  This whole issue is of my own doing, and I believe (hope) quite easy to resolve as outlined above.

My intent here is to ask Forum members if I'm missing something obvious and perhaps forewarn anybody who's about to do a similar thing to make sure they have enough power to start whatever equipment they plan to use.

-19F and breezy here tonight .

Dale

[Kbeitz]

I would try getting the grinder up to speed first with a battery powered drill with a socket adapter.
Then flip on the switch to the grinder and see what happens.
Or you could do like a yoyo. Wrap a string around it and give it a pill start...

[Ianab]

Is it an issue with the generator not going from "no load" to "peak power" fast enough to handle the start-up current?

The voltage browns out, the motor draws too many amps, and the breaker opens to prevent anything bad happening.

It may be that if you added a couple of hundred watts of load to the system, the generator isn't then at idle, and can handle the extra start-up current. Just a theory, but it should be easy enough to test by hooking a steady resistive load like a 200w workshop light to it.

[Kbeitz]

You could also tie in a bank of capacitors to help jump start it...
Or a universal brush motor with a heavy flywheel that would back feed to the system.

[stihltoomany]

Much simpler solution. Just pulse the motor to get it up to speed. Plug in motor, unplug just before the breaker trips, repeat til up to speed. Have done this with a fan in a livestock trailer and a 1000 watt Honda for years. No bad effects yet.

[sandsawmill14]

unless cooks used more than one 1/2 hp motor it pulls 8.8 amp (1056 watts) @ 120 volts 4.4 amps (but still 1056 watts) @ 240 volts   if your generator has 240 volt plug you could rewire motor for 240 and the breaker might hold BUT it may kick the gen overload instead. starting load will be about 3200 watts. i have never checked the amp load while it is grinding a blade but i would guess 6-800 watts depending on how hard of a grind your taking. i would just move it to the power supply and sharpen at night  you really dont want to stop sawing to sharpen blades anyway do you ???

[sandsawmill14]

those numbers are based on a sf of 1 but the motor is actually 1.15  so its off a very little but not enough to change sizing of anything

[hersnsh#590]

Thanks everybody!

stihltoomany:  I'll give that a try, it might work.  The generator almost gets the grinder up to speed as it is.


sandsawmill14:  reluctantly, you're right.  It's a space consideration.  I have the space in the mill shed, and the setter is right there too.  I don't have the space near power that I want to dedicate to the sharpener... but I may have to.

Dale

[pine]

May be obvious but you are not running the Honda in Eco mode when you start the sharpener are you? 
If so turn off Eco mode so the generator is at a higher speed and then try it. 

I agree the companion will resolve the issue. But turn off Eco mode first.

[stihltoomany]

unless cooks used more than one 1/2 hp motor it pulls 8.8 amp (1056 watts) @ 120 volts 4.4 amps (but still 1056 watts) @ 240 volts   if your generator has 240 volt plug you could rewire motor for 240 and the breaker might hold BUT it may kick the gen overload instead. starting load will be about 3200 watts. i have never checked the amp load while it is grinding a blade but i would guess 6-800 watts depending on how hard of a grind your taking. i would just move it to the power supply and sharpen at night  you really dont want to stop sawing to sharpen blades anyway do you ???

This will really help if the motor can be wired for 240 and the gen has 240 volts. Each leg will only pull 1/2 the current of 120 setup. This worked very well for me on an air compressor a long ways from power source. If gen has 240 you are only using 1/2 potential power on 120 volts.

Edit Just reread OP. As I remember the 2000 doesn't have 240volt. So just a tip for some other day. Sorry.

[KirkD]

May be obvious but you are not running the Honda in Eco mode when you start the sharpener are you? 
If so turn off Eco mode so the generator is at a higher speed and then try it. 

I agree the companion will resolve the issue. But turn off Eco mode first.

Yes I was thinking the same thing eco mode on my eu2000 won't cut it on a high amp draw start on something.

[Brucer]

I ran into the same problem when I was shopping for a generator for the dedicated trim saw at my mill.  The saw specs gave a starting load of 2200 W. There was a 2500 W Honda generator on sale at a big discount so I figured that should do it.

Fortunately I took my saw to the Honda dealer and tried out a generator. The generator handled the starting load, but the saw could not quite get up to speed. I knew that would fry the saw motor so I tried a 3000 W generator (not on sale :() and that did the trick.

A long or undersized extension cord can drop the voltage at the saw motor enough to overload it; in my case I was plugging the saw directly into the generator, so that wasn't the problem. The generator just couldn't supply enough current to start the motor.