REXROTH EcoDrive Cs - Computing Phase Current on the Mains

Rexroth EcoDrive Cs Drives Mains and Supply Voltage Connection 6-11
DOK-ECODR3-DKC**.3-CS*-PR02-EN-P
Computing Phase Current on the Mains
To select a suitable mains contactor and fuses for the power connections
it is necessary to first compute the phase current
IN at the mains.
The mains-side phase current
I
N1
is determined out of the mains
connecting power
S
N1
.
Selecting the mains connecting power in the list or compute it according
to the following formula. With multiple controllers, add the individual
powers.
The mains connecting power can be determined
• by selecting the mains connecting power in the list resp. the technical
data
- or -
• by computing it according to the following formula.
Note: With multiple controllers, add the individual powers and, if
necessary, take a coincidence factor into account, because
often not all servo axes require full power simultaneously.
k⋅
⋅⋅⋅
60
2
MITTELEFF
ZWD
π nM
P =
P
ZWD
: required DC bus continuous power in W
M
EFF
: rms torque in Nm
n
MITTEL
: mean speed in min-1
k: factor for motor and controller efficiency
Fig. 6-13: Computing DC bus power
FPS ⋅
ZWDN1
=
SN1: connected load in VA
P
ZWD: DC bus continuous power in W
F: connected load factor due to the non-sinusoidal phase current
Fig. 6-14: Computing mains connected load
Single-phase load:
N1
N1
N1
U
S
= I
Three-phase load:
3U
S
= I
N1
N1
N1
⋅
IN1: mains-side phase current in A
S
N1: connected load in VA
U
N1: voltage between phases of the mains in V
Fig. 6-15: Computing mains-side phase current
Courtesy of CMA/Flodyne/Hydradyne ▪ Motion Control ▪ Hydraulic ▪ Pneumatic ▪ Electrical ▪ Mechanical ▪ (800) 426-5480 ▪ www.cmafh.com