DC drives fulfill the role of an interface between a controller and the DC motor.  It is important that the DC drive match the control signals (voltage and power levels) as well as the signal type (analog or digital).  The DC drive is responsible for producing power conversion, amplification, and sequencing of waveform signals.  Types of DC drives include adjustable or variable speed control, servo control, and integral motion control.  Some DC drives are capable of delivering adjustable or variable speed control.  DC motors are generally small, powerful for their size, and easy to control.  Integral motion control includes feedback and a controller.  Important specifications to keep in mind when searching for DC drives include considering whether or not a brushless DC drive or amplifier is necessary.  Some DC drives operate together with a brushless DC motor.  Types of DC brushless motor drives include sine wave, trapezoidal, hall sensor commutation, and no sensor.  

Important operating specifications worth considering when searching for DC drives include open loop control, position feedback, tach or velocity module, BEMF or voltage control, torque or current control mode, switching frequency, bandwidth, maximum speed, continuous power, continuous output voltage, maximum continuous output current, and peak output current.  Open loop control makes use of a tachometer or other device to monitor motor speed, rather than using position feedback to control the motor.  Position feedback uses position, force, or other feedback to control motor, in addition to speed sensors.  Use of feedback is referred to as closed-loop control.  A tach or velocity mode gives direct feedback of motor speed.  A drive with BEMF or voltage control can run without a tach using the motor’s Back EMF voltage.  A torque or current control module has constant current control and uses current feedback.  Switching frequency is specified for drives with digital output waves, i.e., PWM.  The bandwidth is the frequency range over which the device meets its accuracy specifications. Accuracy is degraded at lower and lower frequencies unless the device is capable of DC response, and at higher frequencies near resonance and beyond, where its output response rolls off. Frequencies in the database are usually the 3dB roll-off frequencies.  The maximum device speed is the speed when the drive is burdened with no external forces, such as weight.  The continuous power is the maximum amount of power the device can output continuously.   The continuous output voltage is the maximum voltage the device can output continuously.  The maximum continuous output current is the maximum current the device can output continuously.  Maximum current value may require additional cooling.  The peak output current is the peak current the device can output.

Types of DC Drives offered by EP Normand

 

The following types of DC Drives are offered by EP Normand:

• DC590P;
• DC512C;
• DC514C; and
• DC506/7/8.