EDUTEC Educatie en Techniek
EEM02/C Recording the Characteristics of DC Machines with a PC
System Description
The LN training system EEM02/C is based on a 300W Dc multifunction machine, that can be operated as a series wound, shunt wound or coumpound wound machine. For generator exercises with the DC machine, an active servo brake is used as a drive. Loading on the motor is supplied by an active servo brake, which can be controlled either manually from a front panel control, or by the CMA software. Sensors are integrated in the brake for detecting speed and torque, so that these values can either be measured on a multimeter (1V/100rpm or 1V/Nm), or displayed on a PC with the DCMA software.
Topics
Serie-, Shunt-and Compound wound machines
 | Connecting and starting |
| Rotation reversing and speed control |
| Load characteristics |
Shunt Wound Machine (seperately- and self-excited)
| Voltage control, shunt wound generator |
| Load characteristics, shunt wount generator |
Series Wound Machine
| Voltage control, series wound generator |
| Load characteristics, series wound generator |
Compound Wound machine
| Voltage control, (self-excited) compound wound generator. |
| Voltage control, (separately-excited) coumpound wound generator. |
| Load characteristics, separately-excited 100% shunt, 100% series, compound generator . |
| Load characteristics, self-excited 100% shunt, 100% series, compound generator. |
| Load characteristics, when compounded, 100% shunt, 100%, 70% and 30% series. |
Computer Connection
The DCMA software provides online measurement of the motor characteristics of DC
machines. The measured values can be displayed as a chart, digital values or as a table.
Operation follows the familiar Windows® techniques with mouse support. A ramp can be
defined for recording the measurements, which is applied to control the active servo brake
so that the motor is continuously braked down to standstill. The following values can be
accessed and displayed:
Speed/Torque
characteristics
Excitation and armature current curves Excitation and armature voltage curves Electrical power,
mechanical power, efficiency.
The LN PC/I1 is used as an interface, which has an integrated microprocessor (type Motorola 68000). A 4-channel isolating amplifier is used for galvanic isolation of the machine voltages and current, connected between PC/I1 and oscilloscope.
