Figure 1. 2HP Machine Set - Induction Machine / PMDC Machine

1 Description

This Motor-Generator set is made up of two coupled machines that are matched in terms of power, speed and torque. The one on the left is a 3-phase squirrel-caged induction motor and the one on the right is a Permanent Magnet Direct Current (PMDC) machine used as a generator for the purpose of this laboratory. Look at the Name Plates of both of the machines to get a feel for their voltage, current, power and speed ratings etc…

1.1 Induction Motor (IM)

The induction machine is wired as a low voltage delta 4-pole machine. The machine is rated for 230 Volts but we only have access to a 208 Volt supply in the lab.

1.1.1 Name Plate

figure 2. Allen-Bradley Bulletin 1329M 3 Phase Induction Motor Name Plate

1.2 Permanent Magnet DC Generator (PMDC)

The PMDC generator will be used with the load box to create a current in the PMDC machine which is proportional to the torque on the shaft by the relationship of τ = kφia . In steady state the torque of the PMDC generator is equal to the torque of the IM, neglecting rotational losses. Therefore to determine the torque of the IM we can assume that the current in the PMDC machine multiplied by the PMDC machine constant will approximately equal the torque of the IM. The machine constant for the PMDC machine is 0.824.

1.2.1 Name Plate

figure 3. Baldor CDP3585 PMDC Motor Name Plate