18
IM483 Operating Instructions Revision R032306
19
IM483 Operating Instructions Revision R032306
in a less than expected current draw on the power supply.
Stepping motor drivers are designed with the intent that a user’s power
supply output will ramp up to greater than or equal to the minimum
operating voltage of the drive. The initial current surge is substantial and
could damage the driver if the supply is undersized. The output of an
undersized power supply could fall below the operating range of the
driver upon a current surge. This could cause the power supply to start
oscillating in and out of the voltage range of the driver and result in dam-
age to either the supply, the driver, or both.
There are two types of supplies commonly used, regulated and unregu-
lated, both of which can be switching or linear. Each have advantages
and disadvantages.
R e g u l a t e d v s . U n r e g u l a t e d
An unregulated linear supply is less expensive and more resilient to current
surges, however, the voltage decreases with increasing current draw. This
may cause problems if the voltage drops below the working range of the
drive.
Fluctuations in line voltage are also a point of concern. These fluctua-
tions may cause the unregulated linear supply to be above or below the
anticipated or acceptable voltage.
A regulated supply maintains a stable output voltage, which is good for
high speed performance. These supplies are also not affected by line
fluctuations, however, they are more expensive. Depending on the cur-
rent regulation, a regulated supply may crowbar or current clamp and
lead to an oscillation that, as previously stated, can cause damage to the
driver and/or supply. Back EMF can cause problems for regulated sup-
plies as well. The current regeneration may be too large for the regulated
supply to absorb. This could lead to an over voltage condition which
could damage the output circuitry of the IM483.
Non IMS switching power supplies and regulated linear supplies with
overcurrent protection are not recommended because of their inability to
handle the surge currents inherit in stepping motor systems.
Table 5.1: Motor Power Supply Specifications
s
n
o
it
a
c
if
i
c
e
p
S
y
l
p
p
u
S
r
e
w
o
P
r
o
t
o
M
n
o
it
a
c
if
i
c
e
p
S
e
p
y
T
y
l
p
p
u
S
d
e
d
n
e
m
m
o
c
e
R
C
D
d
e
t
a
l
u
g
e
r
n
U
e
g
a
tl
o
V
e
l
p
p
i
R
%
0
1
±
e
g
a
tl
o
V
t
u
p
t
u
O
C
D
V
5
4
+
o
t
2
1
+
*
t
n
e
r
r
u
C
t
u
p
t
u
O
k
a
e
P
A
3
r
o
t
o
m
e
h
t
,
e
g
a
tl
o
v
y
l
p
p
u
s
r
e
w
o
p
e
h
t
n
o
t
n
e
d
n
e
p
e
d
s
i
d
e
d
e
e
n
t
n
e
r
r
u
c
t
u
p
t
u
o
e
h
T
*
.
d
a
o
l
e
h
t
d
n
a
n
o
it
c
e
l
e
s
