Wye - Delta on VFD

[katratzi]

I have been reading this thread:

http://forums.mikeholt.com/showthread.php?t=115549


and it has answered a lot of questions, but I have a LENZE
motor that this nameplate data:

LENZE A-4470 Enns Austria
DS100L/4 B9 55 IP

3.6 kw | S1 |lz F

50 HZ | 1400 RPM
wye/delta 220-240 /380-415 Volts
12.6/7.3 Amp | cos 0.81



60 HZ | 1680 RPM
wye/delta 220-266 / 380-460 Volts
12.6/7.3 Amp | cos 0.85


No. 508887 | 1995/50


I connected a siemens G120 VFD to it, tuned it using the
60 hz 460 volt settings, but the motor was wired in the
wye method. It ran ok, but could stall easily, and only
supplied an output of 3.7 amps max before stalling.

So, I rewired the motor to delta, thinking this would fix
the torque issue. The dive could not complete the auto-
tune, it could not even do a standstill saturation tune.
The motor would only oscillate back and forth, and I had a
Siemens drive guy helping me!

To get it running well enough, we had to wire the motor connections
back to the wye configuration, and use the 12.6 max amp
ratings for the drive current parameter (which I thought would
only apply if the motor was using 230 volt supply).

My question is why did the drive have so much trouble
when this six lead motor was wired for delta, and do the dual
voltage ratings on the motor nameplate mean that 230 or 460
volts can be applied to both wye and delta configurations, or
does each wiring method need a specific voltage?


Sorry for long topic, but it was a long night, and I am
trying to learn about getting this done correctly. Thanks.

 

[Jraef]

In a dual voltage Y-Delta wound IEC motor, the Wye winding is typically the higher voltage connection, the Delta is the lower. If you have copied that nameplate data correctly, I too would be confused by what it says. As I read that, they are implying the Y ratings are for 220-240V, the Delta for 380-460V; the opposite of convention.

IEC Nomenclature--6 & 12 Leads:
Dual Voltage WYE-Delta Connections
Volt--Conn.______L1 _____L2_____ L3_____Join
High--WYE______U 1______V1_____W1_____U2&V2&W2
Low--Delta____U1,W2__V1,U2__W1,V2__--------------

So that would explain why the VFD would not auto-tune in Delta. But why were you getting no torque in Wye then? Not clear. Double check your connections first. Looking at the Lenze website for basic motors, they seem to follow the convention listed above, but I don't see that motor listed anywhere.

 

[katratzi]

I left the motor wired up in the wye configuration, and set
the drive parameters for the 50hz 400volt european standard.
I also changed the max current back to 7.3 at 400 volt, as per
the nameplate.

The drive runs fine with no torque loss, and the amp feedback
is more realistic! For example, it runs conveyor at 4.2 amp
current draw, and amp draw increases as more load is applied
as one would expect.

Jraef, I checked the nameplate again, and what I had listed is
indeed correct. So I am also confused.

If a motor is NOT dual voltage, then would I be
correct in assuming to connect it in Delta for drive operation?