Danfoss VLT 3006 Product Manual page 133

132
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
Derating
Derating for air pressure
Below 1000 m altitude no derating is
necessary.
Above 1000 m the ambient temperature
(t ) or max. output current (I
AMB
be derated according to the graph below:
Motor derating for running at low speed
When a centrifugal pump or fan is con-
®
trolled by the VLT Series 3000 it is not
necessary to reduce the output current at
low speed because of the load charac-
Derating for running at low speed
Derating for higher switching frequencies
®
Applies only to VLT types 3002-52 as the
maximum switching frequency is 4.5 kHz
®
set in the VLT types 3060-3250.
A higher switching frequency (para. 224)
results in greater loss and stronger heat
formation in the frequency converter's tran-
sistors and motor coils.
The frequency converter therefore auto-
matically derates the maximum permitted
constant output current I
VLT,N
switching frequency exceeds 4.5 kHz.
Linear reduction is performed down to 60%
at 14 kHz (see graph).
®
MG.30.A7.02 - VLT is a registered Danfoss trademark
1. Derating of output current versus
altitude at t
2. Derating of max. t
at 100% output current.
) must
VLT,MAX
teristic for centrifugal pumps/fans. Motors
running constant load torque applications
at low speed must be derated or force-
cooled (see graph).
Derating for higher switching frequencies
, when the
= max. 40 °C.
AMB
versus altitude
AMB