Fagor DDS AXD/SPD 2.75 - Page 223

Selection criteria
5.
Ref.1912
· 223 ·
DDS
HARDWARE
5.5 Ballast resistor selection guide
Calculate the value of:
Based on the following formulae:
where:
Wm Energy generated by the braking of each system motor.
Pe Rms power generated by all braking of all the motors
throughout a complete duty cycle.
Jt Total inertia of the Power Drive System (motor+mechanics) in
kg.m².
n Turning speed of the motor when the braking starts in rpm.
Wmi Energy of each braking during a cycle of time T in Ws.
Wp Potential energy lost by the machine mass while braking (only on
non-compensated axes) in Ws.
ti Braking time (in seconds) when the Wmi energy is generated.
T Time (in seconds) in a full cycle.
Dh Height (in m) lost while braking.
Wmx Maximum energy among all the Wm.
Pmx Maximum power generated by all the braking, given by the maxi-
mum value among all the (Wmi / ti) quotients of each braking in kW.
W
m
W
p
1
2
---+J
t
2 n

60
--------------
2

Ws=
W
p
mgh=
P
e
W
mi
2
t
i
------------
i

T
---------------------
w=
P
mx
W
mi
t
i
------------



max
kW=