Thermal Warning Output - Hitachi L300P Series Instruction Manual

Suppose the electronic thermal setting (B012) is set to 44 Amperes. The graph below shows the
effect of the free setting torque characteristic curve. For example, at (B017) Hz, the output
current level to cause overheating in a fixed time period is reduced to (B018) A. Points (x), (y),
and (z) show the adjusted trip current levels in those conditions for given trip times.
Trip
time (s)
60
0.5
0
(x)
Reduced trip current at (B017) Hz
Thermal Warning Output – Using parameter C061, you can set the threshold from 0 to 100%
of trip level for turning ON the intelligent output [THM] at that level. In this way, the inverter
provides an early warning before the electronic thermal overload trips and turns OFF the output
to the motor.
Opt.
Symbol Function Name
Code
13 THM Thermal Warning
11, 12, AL0 – AL2
Valid for
outputs:
C061
Required
settings:
Notes:
• The electronic thermal overload function uses
the output current and time to calculate
thermal heating of the motor.
• The thermistor input of the inverter is a
separate function from the electronic thermal
function. You can set a threshold for it to
cause a trip alarm at a particular thermistor
resistance.
(x) = B018 value x 116%
(y) = B018 value x 120%
(z) = B018 value x 150%
A
(y) (z)
Output
State
ON when the electronic thermal calculation
exceeds the set limit
OFF when the electronic thermal calculation is
less than the set limit
Example: (Requires output configuration—
see page 3–48.)
Inverter output terminal circuit
12C
See I/O specs
on page 4–8.
4–49
L300P Inverter
Description
THM
12A 11C 11A
24VDC
+
L
–