Since a small increase in current flow to a motor produces a proportionately larger amount of heat, motor amperage exceeding nameplate values should be carefully investigated as a possible cause. These overload trips, though often caused by motor loading issues, can also indicate bearing failure, insulation breakdown or voltage unbalance.
On circuits protected by GFCIs (Ground Fault Current Interrupters), leakage current can cause unnecessary and intermittent tripping. In extreme cases, it can cause a rise in voltage on accessible conductive parts.
Early reports from the field suggest that the new Fluke 772 and 773 Milliamp Process Clamp Meters may be game changers, breaking new ground for technicians in the HVAC controls industry. With the feature sets these meters offer, troubleshooting of the most common problems in modern control systems becomes a snap.
The safety rated Fluke T+Pro gets field-tested by non-electricians. Larger buttons for gloved hands and a battery life indicator helped to make the transition from the old solenoid-based testers to the T+Pro much easier.