sepam 20 user manual - Schneider Electric

3
Protection functions Starts per hour
ANSI code 66
3/30
Operation
This function is three-phase.
It picks up when the number of starts reaches the following limits:
b maximum number of starts allowed per period of time (P) (Nt)
b maximum allowed number of consecutive hot starts (Nh)
b maximum allowed number of consecutive cold starts (Nc).
The function indicates:
b the number of starts still allowed before the maximum, if the protection has not
picked up. The number of starts depends on the motor’s thermal state
b waiting time before a start is allowed, if the protection has picked up.
Starting is detected when the current consumed becomes greater than 10 % of the
Ib current.
User information
The following information is available for the user:
b the waiting time before a start is allowed
b the number of starts still allowed.
See chapter "Machine operation assistance functions".
MT10871
The number of consecutive starts is the number starts counted during the last P/Nt
minutes, Nt being the number of starts allowed per period.
The motor hot state corresponds to the overshooting of the fixed set point (50 % heat
rise) of the thermal overload function.
When the motor re-accelerates, it undergoes a stress similar to that of starting
without the current first passing through a value less than 10 % of Ib, in which case
the number of starts is not incremented.
It is possible however to increment the number of starts when a re-acceleration
occurs by a logic data input (input I22).
Block diagram
I1
I2
I3
I > 0.1Ib
input I22
0
Characteristics
T
thermal alarm
(hot state)
&
"Clear"
≥ 1
Period of time (P)
Setting 1 to 6 hr
Resolution 1
Nt total number of starts
Setting 1 to 60
Resolution 1
Nh and Nc number of consecutive starts
Setting (1) 1 to Nt
Resolution 1
T time delay between starts
Setting 0 mn y T y 90 mn (0: no time delay)
Resolution 1 mn or 1 digit
(1) With Nc y Nf.
&
k1 > Nt
P mn
k2 > Nc
P mn/Nt
k3 > Nh
P mn/Nt
≥ 1 inhibit
closing
PCRED301005EN - 06/2008