5000 Watt Generator Won't Start A Wilton Square Wheel ???

[MOBILE1]

Has anyone come across this before? I'm a mobile sharpener trying to get my 1 horse 2 by 72" grinder to run off a Generac 5000 watt genset. The Wilton moter is made by Baldor and is rated at 13.8 amps. My generator has more than enough amperage (45) but the Square Wheel is tripping the breakers after about 90 seconds of run time. I've talked to Wilton and Baldor people and the best I'm told is buy a start up control switch($475) and it MIGHT solve the problem.(of course once this switch is installed it is non returnable) I realize some other options may be finding another motor that does'nt suck so many start up amps,(Baldor told me the 1 horse they supply to Wilton draws 70 amps to start!!)or to go with a variable speed which means I've got to switch to a three phase and my rig is already set up for a 1 phase(buffer , Foley Belsaw 390 serretor ETC...) If any of you guys have had to deal with this before please let me know what you did to solve it. Many thanks !!! Dave

 

[m l williams]

Dave, not an uncommon problem. The problem is starting current. An electric motors starting current is 4 to 6 times it's full load current. A motor pulls much higher current on start up than it normally does. On a regular circuit this is no problem because it only lasts for a second or so. But a generator that can not put out the instaneous current required, in this case somewhere between 55 and 85 amps, will not allow the motor to come up to speed. Therefore the motor continues to try to reach breakover speed and can't while the generator trys to catch up on a load that keeps increasing, something will give. A soft starter won't generally work on single phase motors because the motors centrifugal switch won't drop off the amps till it reaches speed; another one of those vicious cycles. The only solution that I can see is a larger generator or a three phase generator with soft starts on your motors. If you buy a new generator have the sales person guarantee in writing that they will take it back if it won't handle your load, better yet hual it down there and hook it up. They won't mind if they can sell a generator. Probably looking at a 81/2 to 10 kw rig though. Hope this helps. mw

 

[Mike Hull]

You can go with a DC variable speed motor and control,1-11/2 hp,that will not cause the circuit tripping problems.I know it is a rather exspensive solution,but I have no idea what your generator is worth or if you can upgrade to a more powerful one for less money than the VS conversion.You will never regret a VS switchover,once you try it you will never go back.

 

[Matt Shade]

If its not a direct drive, you might be able to rig up a way to throw it in and out of gear. It would be pretty tough to get it all figured out but I've seen it done on a few different belt driven machines before. An idler pulley is mounted on a peice of barstock so that it can be swung in an arc and will change the path of the belt.

If you set it up something like this

(drive pulley)==============================( shift pulley)
O (contact wheel pulley)O O
================================
When you swing the lever down, the vee belt runs on the motor and the shift pulley in an oval. When you raise it, the belt contacts the contact wheel pulley and runs in a triangle. I don't know if that would help reduce the starting load enough that that generator could catch up or not.

The only other thing I can think of is that capacitor type motors don't require as much starting power as induction type motors.

 

[MOBILE1]

Hey Guys- Thanks for all your suggestions. It happens that by accident I discovered by feathering the start switch after about 15 seconds of run time I'm able to continue thru to the lower amperage and it kicks into regular run mode! This small revelation saved me the cost of a start up control(that most likley would'nt have solved the problem) and the next step which would have been buying a capacitor start 1 horse and Micky Mousing it to the Wilton. Once again this forumn has proved invaluable to me and my business-THANKS AGAIN / Dave Hammer

 

[Eric M Ericson]

If the problem returns, try replacing your breaker.

sometimes a marginal breaker will give these same symtoms.

(It may not be the case but it's worth a shot)