4.6
50J – Jam and Stall Protection
Functional Description
When the motor is running, a current increase above normal load may be an indication of
a malfunction in the load. JAM protection recognizes mechanical problems, such as broken
drive gears.
The EMR-3MP0 can be configured for a JAM alarm and/or a JAM trip. There are two JAM
elements, »50J[1]«, »50J[2]«.
Refer to the JAM protection limit (the right vertical line in the “Underload and JAM Trip
Function” curve example). In this curve example, the JAM trip is set at 150% of FLA.
0.1
1
10
100
1
1000
multiples of full-load amperes
JAM_F01
10
100
#(t_k) [s]
Underload trip
level (in %
full-load
amperes).
Underload trip
function not active
during underload
start delay
function.
Delay time
determined by
underload run
delay function.
Jam trip function
not active
during jam
start delay
function.
Delay time
determined by
underload run
delay function.
Jam trip level
function (in %
full-load
amperes).
Fig. 42: Underload and JAM Trip Function.
In the “Underload and JAM Trip Function” curve, the Trip settings are represented by two
vertical lines, both well above the normal load current. This curve also applies in case the
JAM function is configured as a JAM alarm. Be sure to set the alarm level below the trip
level.
164
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EMR-3MP0
4 Protective Elements
4.6 50J – Jam and Stall Protection