Possibility the the motor is coasting to a stop and the Regeneration voltage is induced back into the load side of the softstarter. Check the SCR's without power to see if they are shorted.
The PST softstarter has three different voltages levels on it. The Three phase Motor voltage, the (120-220)Vac Supply voltage, and the 24Vdc control voltage. The 24Vdc can be supplied extenally by removing the jumper between terminal 8 & 9. Then put your Negative on Terminal 8 and and use the Positive as a signal to the Stop/Start terminals
For applications requiring braking even when there is incoming supply line loss, the braking chopper will provide braking down to approximately 10% motor base speed. Therefore, in applications where it is critical the load is stopped quickly even if there is power loss, a brake chopper is a good solution.
Yes. The ACS800-U31 includes DC Bus Connection Terminals and an external braking chopper (NBRA type) may be applied. For ACS800-37, cabinet built choppers and resistors are available and may be ordered with a plus code.
The absolute value of the current harmonics generated by the drive is independent of the load current, meaning that the absolute value of the harmonics is nearly the same at no load as at nominal load. That is why the current waveform looks distorted even when the load current is very low. This is not an issue as the harmful effects of harmonics depend on the absolute harmonic content based on nominal load. For example, the standards like IEEE519-1992 refer to harmonic content as a percentage of the total load current.
In principle, one can consider the current distortion generated by an AC drive as fixed, i.e. it does not depend on the character of the network. The voltage distortion depends on the quality of the network. The higher the impedance of the network (weaker the network), the higher voltage distortion is caused by a given current distortion. That is why harmonic requirements are typically given as current distortion. For example, IEEE519-1992 gives maximum allowed current distortion values based on a network's short-circuit ratio.
No, AC line harmonics are caused by many electrical devices and are an overall system issue, not just associated with AC drives. The goal of low harmonic AC drives is to contribute less harmonic distortion to the overall system.
As usage of electronic and electrical equipment increases, users and utilities are becoming more concerned about the harmful effects of harmonics. This is leading to more stringent power quality requirements
An LCL filter is a filter which consists of a inductor (L), a capacitor (C), and another inductor (L) arranged in a T-section configuration. Each input phase of the ACS800-U31 and ACS800-37 includes a symmetrical set of these components. The inductors are series power components that carry the full current of the drive
ABB's ultra low harmonic drive solution uses advanced harmonics mitigation technology that does not require external filters or multi-pulse transformer. These drives utilize an active front-end rectifier with a LCL (inductor - capacitor - inductor) filter. The low line harmonic content of the ACS800-U31 and ACS800-37 AC drives fulfil the strictest harmonic requirements including IEEE519-1992 at the drive's input terminals. This makes ABB's ultra low harmonic drive a simple and compact solution for low harmonic AC drive.