AC versus DC drives

The first electric drive systems were DCalso the drive system of choice for high speed
powered. Although brushless AC motors haveapplications, since they have no commutator
replaced them to a large extent, there is still aproblems. Special AC drive casings are available at
need for DC drives in industry.low cost for areas at risk of corrosion, explosion
Adjustable drives are of particular use inor moisture. This makes them ideal for water
small-scale output (the opposite of bulksystems and chemical plants.
production) where one machine may be used forAC drives are preferred in areas where loads are
several different tasks. Adjustable electric drivesvariable, or there are long runs of light loads
combine high performance and efficiency with– both these cause wear on the
ruggedness, simplicity of operation and low cost.brushes and commutators of DC motors. In
Their task is to control the speed, torque andsystems that require several motors to run at
direction of rotary machinery such as lathes, mills,simultaneous speed, AC drives are obviously the
pumps, conveyor belts and printing presses.better choice.
There are pros and cons to both AC and DCDC drives
drives. AC drives are prized for their dependability,DC motors are less complex than AC motors,
compact size and low maintenance. However, DCand are generally cheaper . This makes them
drives are prized for their low cost, simplicity anduseful for small companies. DC systems are also
versatility.the best choice for regenerative loading
AC drivesapplications, such as escalators and conveyor
3-phase AC induction motors require virtually zerobelts, or in areas where very sensitive control is
maintenance, and are smaller and lighter than theneeded.
DC equivalent. They are therefore more suitableWe at Iconsys supply both AC and DC drive
for areas that are hard to reach, or have spacesystems for a wide range of industrial applications.
or weight restrictions. Being brushless, they are