Pumps and Motors

Practical guides for electricians, technicians, and engineers working with electric motors: testing and troubleshooting, overload and cable sizing, and industrial motor control centers (MCCs). Start with the guides below, or browse every article underneath.

Motor Testing and Winding Resistance

• 3 Phase Motor Winding Resistance Chart by HP (1HP-250HP)
• Submersible Motor Winding Resistance Chart
• Acceptable Motor Winding Resistance Imbalance
• Winding Resistance vs Insulation Resistance

Motor Protection, Sizing and Calculations

• How to Size Motor Overload Protection (Step-by-Step)
• Motor Overload Setting Table (PDF and Excel Download)
• Wire Sizing for Motors: Motor Cable Size Calculation
• Motor Calculation for Conveyor: Power and Torque

Motor Control Centers (MCC)

• Motor Control Center Design Standards
• Motor Control Center for Oil and Gas
• Smart MCC with SCADA Integration
• Siemens vs ABB Motor Control Center
• Rockwell Automation MCC Pricing
• Draw-Out Motor Control Center Price

Quick Guidance

Winding resistance vs insulation resistance: A winding resistance test uses a low-ohm meter to find open windings, shorted turns, and imbalance between phases. An insulation resistance test uses a megohmmeter to check the insulation between the windings and the motor frame. They detect different faults, so run both when troubleshooting.

Overload vs conductor sizing: Overload relays are set from the motor nameplate current, while conductors and branch-circuit protection are sized using code tables (NEC Article 430 in the US, or your local equivalent). Always confirm against the nameplate and the code edition your jurisdiction enforces.

Need a quick calculation? Try our electrical calculators for cable sizing and related motor calculations.

All Pumps and Motors Articles