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E
= the overall energy flowing back to the supply in Joules. In case of a rotary motor
M
and load, E
can be computed with the formula:
M
1
=
+
E
(J
J
M
M
L
2
Kinetic energy
where:
J
– total rotor inertia [kgm
M
J
– total load inertia as seen at motor shaft after transmission [kgm
L
ϖ
– motor angular speed before deceleration [rad/s]
M
m
– motor mass [kg] – when motor is moving in a non-horizontal plane
M
m
– load mass [kg] – when load is moving in a non-horizontal plane
L
g – gravitational acceleration i.e. 9.8 [m/s
h
– initial system altitude [m]
initial
h
– final system altitude [m]
final
I
– motor current during deceleration [A
M
R
– motor phase resistance [Ω]
Ph
t
– time to decelerate [s]
d
T
– total friction torque as seen at motor shaft [Nm] – includes load and transmission
F
In case of a linear motor and load, the motor inertia J
the motor mass and the load mass measured in [kg], the angular speed
speed measured in [m/s] and the friction torque T
Remark: If the above computation of E
for the capacitor can be 10,000 μF / 100V.
Option 2. Connect a brake resistor R
connector J2 and activate the drive braking circuit from EasySetUp when motor supply voltage
exceeds: U
= 55V (IDM240) / 87V (IDM640). This option is not available when the drive is
BRAKE
used with a step motor.
Remark: This option can be combined with an external capacitor whose value is not enough to
absorb the entire regenerative energy E
Brake resistor selection
The brake resistor value must be chosen to respect the following conditions:
1. to limit the maximum current below the drive peak current I
2. to sustain the required braking power:
© Technosoft 2011
ϖ
+
+
2
)
(m
m
M
M
L
Potential energy
2
]
can't be done due to missing data, a good starting value
M
BR
but can help reducing the brake resistor size.
M
R
−
)g(h
h -
)
initial
final
Copper losses
2
]
/phase]
RMS
and the load inertia J
M
will become friction force measured in [N].
F
between pin 4 and pin 8 of the Motor & Supply
= 16.5A
PEAK
U
MAX
>
BR
I
PEAK
31
ϖ
t
−
2
3I
R
t
d
M
M
Ph
d
2
Friction losses
2
]
will be replaced by
L
ϖ
will become linear
M
IDMx40 Technical Reference
T
F
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