Baldor Grinder Capacitors - Low or High Voltage?
Baldor has long been recognized as the premier American brand of grinders and buffers. In order to service the farrier market, they have partnered with FPD to produce units that are easily adapted for use with various attachments such as Expander wheels, Multi-Tools, and various other useful options.
From time to time we get comments from the field about heat buildup in the motor housing. We asked Baldor to provide some technical information as to why that might happen.
Baldor has built units with larger capacitors for the farrier industry so that they will work better under the electrical service conditions we frequently see in barn areas. They do the same thing with some of their Farm Duty motors. Baldor grinders are normally rated for 115/230V, by National Electrical Manufacturers Association (NEMA) guidelines. That means the voltage can fluctuate +/- 10%. So a 230V line can drop to 207V and a 115V can drop to 104V. With anything lower than those voltages, the motors have a difficult time running. Putting larger capacitors in gives the grinder greater torque and starting capacity on low line voltages. With the normal capacitor, the grinders often take longer to start and generate less torque while running - you may even have to spin the wheel to get it started. So, in essence, the larger capacitors on the 1/2 and 3/4 hp grinders perform much better in low or fluctuating voltage situations.
As with many things, there are two sides to the story. When you have larger capacitors that boost the voltage and you run a grinder on a stiff line with a solid 125V or 240V (high side instead of low) then the motor will run a little hotter because the high line voltage now generates much greater torque and the grinder pulls higher amps; in motor terms the motor begins to saturate. As long as the grinders are not left running unloaded for extended periods this is not a problem. If running for extended periods is desired, a lower capacitor value can be purchased to replace the one shipped with the grinder. This applies to the BG12 and BG34 models built for FPD.
How hot is hot? What is hot for some products is not hot for another. All grinders have an insulation class that can withstand up to 130 degrees Celsius (266 degrees F) internal temperatures before the windings begin to break down. This means outer skin temperatures can reach as high as 200 degrees F at maximum temperature. You can boil water at 212 Degrees F so the term running hot should be qualified. Of course running at those temperatures all the time is not good. It can degrade the life of the insulation and can shorten the life of the grinder if you run at those temperatures for extended periods of time, day in and day out.
If you feel you are running in solid voltage situations and your grinder feels too hot, then you can contact your dealer to order a replacement Baldor capacitor that is available from FPD.
NOTE: The smaller capacitor for the BG12 (1/2 hp) is part number OC3006F12 (6MFD/370V); capacitor for BG34 (3/4 hp) is part number OC3016F12 (16MFD/370V)