
7. PARAMETER SETTING
VM-5S
-57-
7-14 SPEED RELAY HYSTERESIS
In Auto Reset mode, the speed relay can be provided with hysteresis to prevent contact chattering
when the rotation speed cycles around the speed relay set value.
Example : The relay operates as shown below if the monitor range is 10,000 rpm
(hysteresis 20 rpm).
(1) Relay operates when the rotation speed exceeds the set value
(speed relay set value 5,000 rpm) (Overspeed type)
(2) Relay operates when rotation speed drops below the set value
(speed relay set value 5,000 rpm) (Underspeed type)
OFF
4980rpm
5000rpm
ON
Speed relay
contact value
Relay output
Measured value
Speed relay hysteresis
OFF
5000rpm
5020rpm
ON
Measured value
Relay output
Speed relay
contact value
Speed relay hysteresis