From the thread thread237-489913 I
From the thread thread237-489913 I
(OP)
From the thread thread237-489913: Temporary service shortcoming 120kW VFD I got the extruder fired up.
We have 83kW available. Motor is 123kW. I preheated the extruder chain using 35kW. Once the old stuff was heated up enough and 90% of the heaters were off, started the dual screw extruder at 5RPM. It ran! We successfully ran all the old flexible material out of the chain.
Current at 5rpm was ~40A
Current at 10rpm was ~50A
Current at 30rpm was ~58A
Current at 40rpm was ~60A
We're trying to understand why an empty extruder running at 40 out of 800rpm is drawing 60A/480V = 50kW with no product in it.
OR, is the amp value on the Snider VFD screen, the Real Power amps or does it include reactive/excitation current too?

We have 83kW available. Motor is 123kW. I preheated the extruder chain using 35kW. Once the old stuff was heated up enough and 90% of the heaters were off, started the dual screw extruder at 5RPM. It ran! We successfully ran all the old flexible material out of the chain.
Current at 5rpm was ~40A
Current at 10rpm was ~50A
Current at 30rpm was ~58A
Current at 40rpm was ~60A
We're trying to understand why an empty extruder running at 40 out of 800rpm is drawing 60A/480V = 50kW with no product in it.
OR, is the amp value on the Snider VFD screen, the Real Power amps or does it include reactive/excitation current too?

Keith Cress
kcress - http://www.flaminsystems.com
RE: From the thread thread237-489913 I
" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden
RE: From the thread thread237-489913 I
If we get the VFD to cough-up the power that will be the Real power.
Thanks for the confirmation Jeff.
Keith Cress
kcress - http://www.flaminsystems.com
RE: From the thread thread237-489913 I
The VFD varies the output frequency so that means it runs the motor at full speed all the time. The available shaft power varies directly proportional to the percentage of rated frequency you apply.
The VFD is a power conversion device. The input current would have been MUCH less than 60A. I'd bet you could have started it with the heaters on. I have no idea what you programmed in the VFD or what was running at 5rpm, but assuming 5RPM out of 1780rpm for a 110kW motor the VFD would have been only drawing a few kW off the source to run the motor at rated output torque.
RE: From the thread thread237-489913 I
I'll be changing the VFD's display to show kW instead of the rather useless -in this situation- amps.
Thanks.
Keith Cress
kcress - http://www.flaminsystems.com
RE: From the thread thread237-489913 I
I heated up the extruder chain then ran the augurs at 10rpm. 50A but it never got off 0.0% power. I then ran it up to in steps to 40rpm. Still 0.0% power. So I clamped an ammeter onto the lines feeding the VFD while at 40rpm. 1.5A!! Probably why it's still showing 0.0% when FLA is like 205A.
Thanks LH you were right-on.
Keith Cress
kcress - http://www.flaminsystems.com
RE: From the thread thread237-489913 I