4.5
Fuses
CAUTION:
Never use this instrument in a system that uses more power or
current as listed in Section 2.1, Specifications on page 9.
The controller is shipped from the factory with fast acting fuses rated for the
maximum capacity of the instrument.
If the controller is connected to a system which uses less than 10 amps, the
fuses will need to be changed in order to be correct for the system. Once the
controller is connected in the system, the system current needs to be measured
or calculated and the appropriate fuse size and characteristics selected. Gener-
ally, the fuse selected is rated at 125% of the maximum current of the system.
The time-current characteristics of the fuse are selected by the application.
Usually, fast acting fuses are selected systems without a high in-rush current,
i.e. "hot" calibration baths. Time-delay or slow blow fuses are selected for sys-
tems with a high in-rush current, i.e. "cold" calibration baths. Refer to the
fuseology section of your fuse catalog for help in determining fuse size and
characteristics or contact an Authorized Service Center (see Section 1.4) for as-
sistance. Once the correct fuse characteristics and rating of the fuses have been
selected and the appropriate fuses placed in the power entry module of the in-
strument, mark the instrument so the user can visibly see the fuse size and rat-
ing for fuse replacement. Be sure to change both fuses to the new rating and
correct characteristic.
The controller uses 0.2 amps of current. This current should be taken into con-
sideration when calculating the system power.
Example when using the power of the system:
P
= Power of the system (Total Watts)
V
= Nominal line voltage (115 VAC or 230 VAC)
I
= Fuse current
I
P
V
=
×
×
1 25
0 9
.
.
Example when using the system current:
I
= System current
I
f
= Fuse current rating
I
I
f
=
×
1 25
.
15
4 Installation
Fuses
