HOW VULNERABLE IS CNC MACHINE, ROBOTICS & AUTOMATION TO POOR QUALITY?
Drives and servo drives are employed in CNC machines, Robotics and automation. These drives drive AC motors or Dc motors. They tend to generate harmonics especially the 5th and 7th harmonics, besides other harmonics, but the 5th and 7th are the dominant ones. The 5th Harmonic tend to affect the forward movement of motors as they are negative sequence harmonics, and the 7th harmonics tend to push the motor forward. In the process the negative and forward push tends to cause torsional vibration in the motor, which causes stress on the motors like heating and eventual bearing failure. These harmonic create multiple ZERO CROSSING leading to misoperation of the digital circuits and ultimately failures. The drives itself is affected due to notching created by commutation of the switching devices like the diodes or mosfets. These harmonics have a direct effect on the performance of CNC machine, their reliability and therefore their productivity of automated machines and robotics. Hence to make automation successful and to extend the life of automated machines it is imperative to mitigate harmonics and improve power quality for a successful automation programmer. The reliability of the drive which is the heart of the machine has to be protected from Harmonics.
Many CNC machine manufacturers were hitherto employing Isolation transformer delta WYE either 1 : 1 or stepdown 240 V AC. While the isolation transformer may be effective in isolation and protecting the personnel from shock, and preventing earth current leakage and keeping the earth neutral voltage below 2 volts, they do not protect the drives or the digital circuits from harmonics.
Description and why Harmonic busting transformer much better than Isolation transformer ?
The novel, innovative harmonic buster which can replace both conventional Isolation Transformer or K rated , is custom Made phase shifted transformer, with or without isolation and necessary electrostatic shielding are cost effective, reliable. It effectively mitigates Harmonics to the extent of > 90%. These Transformers need not be overrated or K rated to factor in the Harmonics that tend to overheat the coils and makes the transformer efficient. The unique technique of Harmonic cancellation prevent the transformer from Heating. The efficiency can be as much as 97%. (As the copper and iron losses are kept at the minimum due to Harmonic cancellation). This harmonic buster renders the isolation transformer obsolete. The harmonics are mitigated to IEEE-519 standards while the voltage waveform improves considerably. In this way The performance, efficiency, reliability and life cycle of the machine is enhanced dramatically.
Benefits of the Drive Harmonic Buster transformer:
# 5th and 7th harmonics are almost completely removed.
#Protects the drives from upstream and down stream Harmonics.
# voltage distortion < 3%.
# Less heat in Motors due to absence of Harmonics. Less noise.
#Healthy Electrical environment with better power quali
# Increased system capacity and reliability.
# less downtime due to failures and malfunctions of equipment.
#Improved Power quality throughout the system.
# The Harmonic buster Transformer has no moving parts and hence very High Mean time between Failures (MTBF).
# power factor improves to > 0.9Hence no power factor improvement required with the attendant risk of resonance.
# Saves energy.
The WAVEFORMS HARMONIC BUSTER TRANSFORMER employs the best and most effective technique of cancelling harmonics and does not involve the risk of installing capacitors or tuned filters, which means adding the risk of electrical resonance and overloading the capacitor filter due to dynamic nature of loads.
Sizing : The transformer rating can be designed for the KVA rating of Drives.
Isolation: When High frequency Isolation is required, the shielding option may be given.
Isolation is optional and will add up to cost.