Anyone have any info on the ABB ACS 550-01 VSD's please? I am particularly looking for how the motor thermal protection works as I want to model the thermal hot and cold curves in SKM's PTW. Any formulae or thermal curves will be most useful.
Thanks.
Maybe the following illustration will help:
The yellow lagging current flows from the source to the motor regardless of whether there is a capacitor bank or not. The blue leading current flows from the source to the capbank regardless of whether there is a motor or not. The NETT effect is a...
Mate, a capacitor is not a source of steady state power - real or reactive. It can only discharge stored electrical energy back into the system when system volts drop below capbank volts (if it has any). This is very different to a solar panel which is a generator in essence.
I'm a bit puzzled...
My capbank is attached at the same bus as the VFD.
backn4life - Capbank is not a source of electrical power in the greater scheme of things since over one complete cycle the nett influx of electrical energy to the capbank is 0 (neglecting small resistive losses). On a network scale, the capbank...
jghrist
I hear what you say and I fully grasp that analogy, it is synonomous to the belief that a capacitor bank supplies the vars to the local load. This is in reality a misnomer as the capbank is neither a source or sink of electrical energy. In reality the capbank draws leading current from...
For the harmonics gurus,
I have read in quite a few texts on power system harmonics that a VFD is a non-linear load and so is a source of harmonics. Thinking about it I would say that this is misnomer (the way I see it anyway). The VFD is not a source or sink of electrical power. Considering a...
I have worked with 19000/1 CT's for a 660MW generator for protection purposes. But yes, what are the CT's for? If for protection please state what kind of protection.
Ah yes, I see now in PTW that it has a bus scan impedance magnitude vs harmonic order. It assists in flagging potential resonance issues for a given harmonic(s).
I've just done a harmonic study using PTW. This tells me what the V_THDV% and I_THD%, Vrms, Irms are at several locations in the network, the K factor for trfrs, etc. I was thinking, is there a way of predicting if there are potential resonance issues on the network? The network has several LV...
I certainly concur with both statements above provided it is practically possible. In a pure TT system there is no PE from the load to source. However, all loads within an installation should be bonded together, agreed.
I am still yearning for someone to enlighten me as to the answer to my...
