Technosoft IBL2403 Series, Technical Reference

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©
Technosoft 2007 35 IBL2403 Technical Reference
In order to avoid this situation
add a capacitor on the motor supply
big enough to absorb the
overall energy flowing back to the supply. The capacitor must be rated to a voltage equal or
bigger than the maximum expected over-voltage and can be sized with the formula:
Drive
NOM MAX
M
C
U U
E
C
−
−
×
≥
2 2
2
where:
U
MAX
- is the over-voltage protection limit expressed in [V]. You can read this value in the
“Drive Info” dialogue, which can be opened from the “Drive Setup”.
C
Drive
- is the drive internal capacitance ( 220
μ
F)
U
NOM
- is nominal motor supply voltage expressed in [V]. You can read this value in the
“Drive Info” dialogue, which can be opened from the “Drive Setup”.
E
M
- the overall energy flowing back to the supply in Joules. In case of a rotary motor
and load,
E
M
can be computed with the formula:
F
M d
d Ph
2
M
final initial L M M L M M
T
2
t
t R 3I ) h - g(h ) m m ( ) J (J
2
1
E
ϖ
− − + + ϖ + =
where:
J
M
– total rotor inertia [kgm
2
]
J
L
– total load inertia as seen at motor shaft after transmission [kgm
2
]
ϖ
M
– motor angular speed before deceleration [rad/s]
m
M
– motor mass [kg] – when motor is moving in a non-horizontal plane
m
L
– load mass [kg] – when load is moving in a non-horizontal plane
g – gravitational acceleration i.e. 9.8 [m/s
2
]
h
initial
– initial system altitude [m]
h
final
– final system altitude [m]
I
M
– motor current during deceleration [A
RMS
/phase]
R
Ph
– motor phase resistance [
Ω
]
t
d
– time to decelerate [s]
T
F
– total friction torque as seen at motor shaft [Nm] – includes load and transmission
In case of a linear motor and load, the motor inertia J
M
and the load inertia J
L
will be replaced by
the motor mass and the load mass measured in [kg], the angular speed
ϖ
M
will become linear
speed measured in [m/s] and the friction torque T
F
will become friction force measured in [N].
Kinetic energy Copper losses Friction losses Potential energy