Emerson FM-3 Guide de l'utilisateur télécharger pdf (Page 41)

Epsilon Eb and EN Drives Reference Manual

Figure 12: RMS Foldback Trip Point (this graph is accurate to ±5 percent)

Stall Foldback

EN Only

Stall Foldback prevents overheating of the Power Stage. It activates in any mode when the

motor velocity is 100 RPM or less and the Torque Command causes the current to exceed

the stall current threshold for 100 ms or more.

Note

The stall current threshold is not the same as the drives continuous current rating. For

example, the E

N-204 has a continuous rating of 4.5 Amps but a stall current threshold of

7 Amps.

Stall Foldback will also be triggered when the drive sees repeated high currents in one of the

three motor phases. This can occur when a motor is indexed back and forth between two of

its electrical poles.

• For 4 pole motors such as MG-205 or MG-208 this distance is 90° mechanical.

• For 6 pole motors such as MG-316 through the MG-4120 this distance is 60° mechanical.

• For 8 pole motors this distance is 45° mechanical.

Once Stall Foldback is activated, the drive current is reduced to 80 percent of the stall current

threshold until the Torque Command Actual is reduced to less than 70 percent of the stall

current threshold for about 200 ms or until the motor velocity exceeds 100 RPM.

1 2 ... 36 37 38 39 40 41 42 43 44 45 46 ... 262 263

Pas de commentaire

Emerson FM-3 Guide de l'utilisateur Page 41