Now that you have picked the Nexus Grinder you want, you need to figure out how to power the motor — or the VFD and motor. Below is some information to help you make a decision based on the power available in your garage or shop.
The single biggest factor is what power you have available. Most garages have limited circuits — typically 115 volt 15 amp circuits running the lights, a few plugs, the garage door opener and maybe a central vacuum. If your service panel or a sub-panel is located in the garage or shop, you will have more options. If the panel is in the house, you may have limited ability to run a new circuit out to the garage.
*Note: the information provided here is a recommendation only. You should always consult with a qualified electrician.
Power setups at a glance
230 volt supply with a 20 amp breaker
If you have 230 volt supply, you can easily run a 2 hp motor and a VFD. All you need is a 20 amp double-pole breaker and 12/3 conductor wire from your panel to the VFD and motor. With 230 volts you can use a KBAC-27D or KBAC-24D with a 3-phase motor. If you go with a single-speed single-phase 230 volt motor, you can run most motors up to 2 hp easily.
115 volt supply with a 25 amp breaker
Here you are a little more limited. You can run a KBAC-27D with a 1 hp or 1.5 hp 3-phase motor. On a 115 volt supply the KBAC-27D draws a maximum of 22 amps and requires a 25 amp breaker and 10/3 conductor wire from the panel to the VFD. You can also run single-speed single-phase motors up to 2 hp (check the motor ratings).
115 volt supply with a 20 amp breaker
You can run a KBAC-24D with a 1 hp 3-phase motor. On a 115 volt supply the KBAC-24D draws a maximum of 14.4 amps and requires a 20 amp breaker and 12/3 conductor wire from the panel to the VFD. You can also run single-speed single-phase motors up to 1.5 hp (check the motor ratings). Note that single-phase motors draw the most amperage during the initial startup.
115 volt supply with a 15 amp breaker
This is the most common garage setup. For the KBAC-24D, KB Electronics recommends a 20 amp breaker. Their technical help desk has stated the KBAC-24D can operate on a 115 volt 15 amp circuit — start the drive at a slower RPM and increase gradually to reduce the amperage draw on startup. Research which circuits you have available and check whether anything else is running on the same circuit first. We highly recommend a 20 amp circuit.
Another option is a single-speed 3600 RPM single-phase motor on a 15 amp circuit. Most single-phase 1 hp motors draw a maximum of 13 amps; a 1.5 hp single-phase motor draws a maximum of 14.5 amps. Again, single-phase motors draw the most amperage during the initial startup.
Make sure you have the required power supply and circuit(s) with the correctly rated single- or double-pole breaker and conductor wire before running the motor or VFD. See the KBAC Table 4 electrical rating chart for more detail, and always check the motor information plate for its electrical ratings.
Shop motors, VFDs & wiring
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KBAC-27D Variable Frequency Drive
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KBAC-24D Variable Frequency Drive
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2 HP 3 Phase Motor
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Frequently asked questions
Can I run a 2×72 grinder on a standard 115 volt 15 amp circuit?
Yes, within limits. A KBAC-24D VFD with a 1 hp 3-phase motor can run on a 115 volt 15 amp circuit if you start at a slower RPM to limit startup current — though a 20 amp circuit is strongly recommended. A single-speed single-phase 1 hp motor is another option on 15 amps.
Do I need 230 volt power to run a 2 hp motor?
For a 2 hp motor, 230 volt supply with a 20 amp double-pole breaker and 12/3 wire is the easiest setup. You can run smaller 1 to 1.5 hp motors on 115 volt, but 2 hp is best on 230 volt.
What breaker and wire does the KBAC-27D need?
On 115 volt it draws up to 22 amps and needs a 25 amp breaker with 10/3 wire. On 230 volt it draws up to 16.7 amps and needs a 20 amp breaker. Always confirm against the KBAC manual and your motor plate.
Should I use a VFD or a single-phase motor?
A VFD gives you variable speed and forward/reverse but requires a 3-phase motor. A single-speed single-phase motor is simpler and cheaper to wire, but runs at one fixed speed. Pick based on whether variable speed matters to your grinding.
Working on electrical circuits can be hazardous. Consult a qualified electrician if you are unsure how to make safe connections. All connections should meet or exceed national, provincial and local electrical codes.