I've seen a thesis describing the theory behind it, if I can find it online I'll post a link. The front end IGBT's are effectively switched at the line frequency (50-60Hz), by a hardware comparator-type circuit, and if you ask the IGBT module manufacturer nicely, they can even supply modules...
Hi, DickDV,
There are Siemens products which use this technology. The PM250 power modules from the Sinamics G120 range are the standard drive version, there are distributed versions for conveyors (G120D) and also inverters and motor starters for the ET200 range.
/end sales mode/
Cheers,
Mort
There is a third way, at least I don't recognise Jraef's first description as the same method....
The input bridge has an IGBT across each diode. This bridge is controlled so that the pair of diodes which are conducting at any one time have their complementary IGBT switched on. This means that...
Gunnar, Your description of the sensor use in these applications (If its hot, turn it down), is exactly how I see it being used. Unfortunately, we've been tied down to this spec (it seems for now), so we have to try and meet it. Unfortunately there isn't another measuring method we can use, as...
Hi, all,
thanks for the information, it mostly confirms what we thought. But, given that we are in a lab and rarely (if ever) get out in to the field, we wanted to get some more opinions.
ykee: your comment:
"and since most settings are hidden from occupants, or are relative, this tolerance...
Hi, All,
I'm after some background info regarding HVAC applications.
We're working on an analogue input circuit for Ni1k sensors, and I'd like some background info such as:
1. Typical applications - building heating & air con, ovens, etc.
2. Typical temperature ranges - ties in with the above...
I'm sure he wasn't - I was joking....
Looking at the 1LA7 motor guide - 22kW 4 pole is rated at 41.5A at 400V/50Hz, frame size is 180L.
6 pole 22kW is 200L frame size, but rated current is 45.5A.
Could kentokyo give us the MLFB of the plate, that would shed some light on it? I don't see him...
Gunnar,
I hope they didn't mention Congleton with regard to their problems - we're having a bad enough time as it is at the moment :-)
Ozmosis - I'm afraid I have to disagree with your comment re. motor voltages. The 230/400 configuration is shown as standard up to 45kW in the motor catalogue...
Hi,
What does the drives output current read, compared with the rated current for high PWM frequency? If the drive is derating the pulse frequency it sounds like it's reacting to an overload of current or temperature.
The only other cause I can think of for the problem you describe is a missing...
Hi, All,
I find reading this forum very interesting. I contribute very little as I don't work in the real world that you all inhabit - nicely cocooned in a D+D lab :-)
As a matter of interest to me, I would like to know:
What feature/function of a drive do you wish was available most often? Do...
Matthew,
There is an IP65 ET200 drive available (just released), but I think it's a max. of 1.5kW. It was developed in parallel with the G120D distributed "standalone" drive - up to 7.5kW, IP65. The MM4 range are gradually being superseded by the Sinamics range, which are a significant step...
Hi, dpc,
We spend a great deal of time during development working out / confirming by test various deratings for different situations. The problem is that all of this information can't be included in the basic documentation, but it is available via the support website and/or Customer Support...
Does the Durapulse drive run in sensorless vector by default, or did you go through all of the setting up for it? It could be that by modelling the motor correctly (which may not have been the case on the old VFD) you introduced the improvement in performance. IME most VFDs run in V/Hz by...
Matthew,
Not sure if you are aware, but there is an ET200 VFD module available with full Safety Integrated functionality (Safe stop, Safe ramp down, Safe Low Speed). Power modules are 0.75W-4kW, and it plugs on to the back plane, along with the rest of the ET200 kit. Sounds like it may be the...
dpc,
You said:
"they don't all provide exactly the same data for the overload condition. That would be too easy. Some give it at 125%, some at 150%, etc. "
Check, point taken.
I'm not sure if this is true for other drives, but the example I gave is capable of an average of 110%. The example...
