Echo Electric Motors

Reference Locked Rotor Code Le ers & Reduced Voltage Star ng Methods con nued Solid State Starters A newer type fo motor starter that has become popular is the electronic starter. These devices have the capability of ramping the voltage applied to the motor up (or down) an adjustable period of me. These starters have some simple adjustments such as:

Ini al voltage at start ▪

X

▪ Time of voltage ramp up

X

▪ Time of voltage ramp down Current limi ng during start ▪

X

More sophis cated units have more extensive adjustments that allow for adjustment of many other parameters. Some of these units have provisions for tachometer feedback that can be used to produce linear accelera on rates. In pumping situa ons, both ramp up and ramp down features can be important to reduce the effects of water hammer when star ng or to reduce the effect of water hammer from check valves slamming shut during stopping. Since some energy is lost in the control electronics, larger sizes of these controls will frequently be supplied with bypass contactors that bypass the electronics once the star ng cycle is over, thus elimina ng the running losses. Summary Overall, it is important to note that one of the primary objec ves of reduced voltage star ng is to limit the inrush current to a value that the power system of the local u lity will accept. There are fringe benefits derived from all types of reduced voltage star ng. Reduced torque values that result from the lower applied voltage also reduce wear and tear on couplings, belts, gears and other equipment that is being powered by the motor. Solid state starters offer a smooth transi on from stands ll to full speed with reduced line current, controlled motor torque and accelera on.

©2017 ABB. Technical Papers, Cowern Papers 9AKK107303

142

echogroupinc.com

motors@echogroupinc.com