Servotronix CDHD Series User Manual page 118

Drive Setup
E
frict ion
T
f
ω
1
ω
2
t
d
D e t e r m in in g t he Ene r gy t o be D issipa te d by t h e Am plifie r
E = E - E
M dec
Where:
E
M
I f t his energy is less t han t hat which t he bus m odule can st ore, no regenerat ion
resist or is needed.
E should be expressed in j oule. The conversion rat io from ft ·lb t o j oule is:
M
1 ft ·lb = 1.356 J
D e t e r m in in g t he Ene r gy t h e Bu s Ca n Absorb
1
E = C�V
BUS
2
E
BUS
C
V
M
V
NOM
Det erm ine if a regenerat ion resist or is required
I f E > E
BUS
I f E < E
BUS
D e t e rm in in g Re sist or Va lu e
The procedure for calculat ing regenerat ion requirem ent s is t wofold. Bot h t he
regenerat ion resist ance value and t he resist or wat t age m ust be det erm ined.
D e t e r m in in g t he Resist a nce Va lue
V
R =
Max
V I
B
Where:
V
=
B
V
=
M
K
=
B
N =
118
= Energy dissipat ed by frict ion ( J or ft ·lb)
= Frict ion t orque ( N·m or lb·ft )
= Speed at t he st art of decelerat ion ( rad/ s)
= Speed at t he end of decelerat ion ( rad/ s)
= Tim e of decelerat ion ( s)
- E
m ot or frict ion
= Tot al energy t o be dissipat ed by t he am plifier ( J or ft ·lb)
�
2
2
- ( V )
M NOM
= Energy t he bus m odule can absorb ( J)
= Bus m odule capacit ance ( F) ; see sect ion Bus Specificat ions
Nom inal bus volt age = √2V
= Maxim um bus volt age ( V) ; see sect ion Bus Specificat ions
=
Regenerat ion resist or is not required.
M
Regenerat ion resist or is required.
M
√3
2
M
M
N - � 3I
Mot or back EMF less m ot or losses.
V = K
B B M
Maxim um bus volt age ( V) ; see sect ion Bus Specificat ions
Back EMF const ant ( V L- L / rpm )
m ot or speed prior t o decelerat ion ( rpm )
( V)
m ains
( R / 2)
M
CDHD
User Manual