Variously called intelligent motors, smart motors or integrated motors and drives, these units combine a three-phase electric motor and a pulse width modulated inverter drive in a single package. Some designs mount the drive components in what looks like an oversize conduit box. Other designs integrate the drive into a
Year: 2014
Direct current drives are easy to apply and technologically straight forward. They work by rectifying AC voltage from the power line to DC voltage, then feeding adjustable voltage to a DC motor. With permanent magnet. DC motors, only the armature voltage is controlled. The more voltage supplied, the faster the armature
Major maintenance, troubleshooting and repair of drives should be left to a qualified technician, following the drive manufacturer’s recommendations. However, routine maintenance can help prevent problems. Here are some tips: • Periodically check the drive for loose connections or any other unusual physical conditions such as corrosion. • Vacuum or
As PWM AC drives have continued to increase in popularity, drives manufacturers have spent considerable research and development effort to build in programmable acceleration and deceleration ramps, a variety of speed presets, diagnostic abilities, and other software features. Operator interfaces have also been improved with some drives incorporating “plain- English”
One drawback to pulse width modulated drives is their tendency to produce voltage spikes, which in some instances can damage the insulation systems used in electric motors. This tendency is increased in applications with long cable distances (more than 50 feet) between the motor and drive and with higher-voltage drives.
By definition, adjustable speed drives of any type provide a means of variably changing speed to better match operating requirements. Such drives are available in mechanical, fluid and electrical types. The most common mechanical versions use combinations of belts and sheaves, or chains and sprockets, to adjust speed in set,
When a current-carrying conductor is placed in a magnetic Field, it experiences a force. Experiment shows that the magnitude of the force depends directly on the current in the wire, and the strength of the magnetic Field, and that the force is greatest when the magnetic Field is perpendicular to
Actuators are operated in the same way as solenoids. They are used to move mechanisms remotely. Some examples of actuators on a vehicle are, door locks, pre-engaged starter motors and fuel cut off valves. Consider the diagram below. Like a solenoid or relay an actuator has a winding. When current
A solenoid is the term used for a heavy duty relay and like a relay acts as a switch saver. Solenoids are used to switch circuits that require a very large current to operate. An example of this type of circuit is the starter circuit. Consider the diagram below. Since the
This is sometimes known as an ‘either/or’ relay because you can use either one circuit or the other. This type of relay is particularly useful for headlights. Pin number 87A feeds the dipped beam circuit. When the driver selects main beam the relay is energised so the moving contact moves to
