The Basic Operation of DC Drives
Due to their reliability, simplicity, favourable cost, and ease of use, DC drives have long been an important cog in the wheel that is industrial applications. DC drives are commonly associated with a silicon controller rectifier (SCR) power conversion. The SCR, (also known as a thyristor) converts the fixed voltage alternating current (AC) of the power source to an adjustable voltage, controlled direct current (DC) output which is applied to the armature of a DC motor.
SCR’s provide a controllable power output by means of phase angle control. This term refers to the firing angle of the SCR (a point in time where the SCR is triggered into conduction). It is thus synchronized with the phase rotation of the AC power source. If the device is triggered early in half cycle, maximum power is delivered to the DC motor, whereas late triggering in the half cycle provides minimum power. The effect is similar to a very high speed switch, capable of being turned on and conducted off at an infinite number of points within each half cycle. This occurs at a rate of 60 times a second on a 60 Hz line, to deliver a precise amount of power to the DC motor. The efficiency of this form of power control is extremely high seeing as a very small amount of triggering energy can enable the SCR (Silicon Controlled Rectifier) to control a great deal of output power.
Types of DC Drives offered by EP Normand
The following types of DC Drives are offered by EP Normand:
