Wiring of the Electric Motor

By Irri-Gator Products (Pty) Ltd

Star & Delta ConnectionsStar & Delta Connections•Star connections draw less power than Delta but have low Torque

•Delta connections have more Torque and draw more Power

•Some motors can be wired in Star or Delta, others can be only Star or only Delta, this depends on the Voltage between Phases as well as the make of Motor.

• Most South African motors are 380 VAC 3-phase and American are 220 VAC 3-phase

•Very important to check the Identification plate on motor

•Different terminology sometimes used – Delta = Mesh / Star = Wye

Star + Delta Motor ConnectionsStar + Delta Motor Connections

EarthingEarthing•VERY, VERY important for the drive to be earthed properly

•Neutral and Earth to be separate from one another

•Use a separate copper earth wire not only cable armouring

•Earth wire to run from transformer supply or to have a proper earth mat in ground

•Earth wire to be at least the same size as power feed cable not thinner

•The Ground Resistance must not exceed 10 ohms

Cable LengthCable Length• Cable length to motor must be within specs.

• Do not exceed 50 meters length of cable to motor without consulting us

• This is because of possible current leakage and it may require an output reactor to be fitted

• Important to remember when considering borehole applications

NoiseNoise

• Two types of noises can be apparent:

• 1. Acoustic noise happens on the carrier frequency – this can be corrected in settings on the drive.

• 2. Electromagnetic / Static interference towards electronic or GSM type of equipment can be found – use of screened cables can prevent this, or positioning of the drive away from these devices.

An output EMC filter can be fitted to output of drive

Power Factor CorrectorsPower Factor Correctors

• Drives from 18,5 kW to 90 kW have built in DC reactors, sizes above 90 kW can be considered and then need to be fitted separately

• No capacitors must be fitted to output of system ! Check with supplier!