ABB ACSM1 Series, Системное руководство

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12
Power requirements
In a common DC system several ACSM1 drive modules are connected to
DC link. Each drive and motor has its own specific load cycle profile. The
sum of these load cycles will define the system power profile in DC link as
shown in the figure below.
DC link power P
dc,mot
of motoring axis
P
dc,mot
is the power supplied to the DC terminals to get the required
mechanical motoring power on the motor shaft. P
dc,mot
is higher than the
shaft power, because it covers also the losses in the ACSM1 and motor.
P
dc
: DC link power
k
eff
: Efficiency factor (1/eff) to include ACSM1 and motor losses. If not known, value 1.25 can be
used.
P
m
: Motor mechanical shaft power
T
: Torque (Nm) on motor shaft
n
: Motor shaft speed (rpm)
DC link power P
dc,gen
of regenerating axis
P
dc,gen
is now the power supplied from the regenerating motor to the DC
terminals. P
dc,gen
is lower than the shaft power, because the shaft power now
covers also the losses in the ACSM1 and motor.
Drive
A
Drive
B
Drive
C
M M M
m eff mot , dc
P k P
× =
9550
n T
) kW ( P
m
×
≈
P
dc,mot
ACSM1 losses
Motor losses
P
m
P
m
ACSM1 losses
Motor losses
P
dc,gen
eff
m
gen , dc
k
P
P
× =