Numeric Motor Protection Relay for LV Motors (LCD – Split Module) : mPRO-200

Range

Operational Current:2 – 8.0 x IFL
Frequency Range: 50/60 Hz
Design Standards (As per IEC 60947): IEC 60947-4-1, IEC 61000-3-2, IEC 61000-3-3, IEC 60947-4-1

Features

Monitors the flow of the current from which the following operational conditions of the motor are gathered:-STOP, START & RUNNING
Allows user to enable fail safe operation for DO-1 contacts.
When mPRO generates a trip signal, the DO-1 relay coil is de-energized
Short circuit protection is provided by tripping the relay when the motor operating current in any of the three phases exceeds the value corresponding to Short circuit setting
During a phase loss, the motor winding current will increase by 150% or more

Presentation

In mPRO-200 the protection feature is based on mathematical model of motor thermal image. The motor thermal overload protection function calculates the heat accumulated in the rotor and stator based on the effective heating current , integrated over a time. The relay appropriately takes in to account cooling of the winding by gradually emptying the accumulated current bucket. The relay displays the status of thermal condition of motor windings as a % of maximum permissible Thermal capacity. If inverse overload characteristic (lN\/) is selected then only the effect of thermal memory phenomenon is enabled. If current in any of the three phases exceeds over-current setting l> as well as accumulated thermal capacity (Thermal MEM) is >=100% then mPRO will trip the motor. If thermal memory is accumulated then Relay Contact Reset depends on Relay Reset selection (AUTO/MANUAL) and Thermal Reset selection (Disable/Enable).

Mechanical equipments such as pumps orfans can be quickly damaged if it jams, resulting in a locked rotor stall. The MPro will trip when the running current exceeds the set value (Stall) value after the Stalled Rotor Time (tStall). Set this value to ‘OFF’, if stall protection of driven equipment is not required since the thermal overload protection will protect the motor. This feature is blocked during the inrush of motor starting.mPRO provides protection against over temperature by monitoring the temperature in the motor winding. High winding temperature is caused by phase unbalance, phase fail, high torque starting, insufficient cooling etc. mPRO will trip the motor in running condition after PTC trip time (tPtc) expires. once temperature monitored via external PTC thermistor exceeds the PTC Trip value (PtcTrp).

Benefits

The phase unbalance condition is checked only during running condition of the motor
In the event of phase reversal, the relay trips after set time tPhRev. It helps to protect a three phase motor while installation
During motor start-up, a locked rotor is detected with the state of increased phase current above the set value (LKR) even after the set start time (tLKR)