For safe, long-term use of a compressor, the motor winding temperature must be kept below certain limits, in all conditions in which the appliance may operate. For example, compressors from AC ...

Measuring the electrical resistance (ohms) of motors, compressors, and other electrical devices in HVAC systems may seem straightforward. But when the measurements of zero (0) or “OL” (overload) come ...

Transformers are very reliable devices and can provide service for a long time if regularly maintained and serviced. They’re also the single most costly item in any substation. To protect against ...

The Tettex 2293 from Swiss firm Haefely Test AG is the result of extensive research and years of experience testing transformers. A simple one-time-connection system, together with the simultaneous ...

In the first installment of this series, "Calculating a practical hotspot safety margin", we discussed how two-parameter thermal models assume that the entire motor, including windings, exhibits one ...

Got a motor down? No matter how urgent the problem — and motor failure can cause some very urgent problems — always develop a plan of attack before you start repair work. Gather up any background ...

Whenever a power or distribution transformer is isolated from the power system, it is probable that residual magnetism remains in the core due to the phase shift. However, residual magnetism also ...

A new edition of the only American national standard for repair of motors and generators — “ANSI/EASA AR100-2010: Recommended Practice for the Repair of Rotating Electrical Apparatus” (ANSI/EASA AR100 ...