20 November 2020
A mechanical brake can be controlled by the ATV31 / 312 / 320 drive R1 or R2 relay output. It is preferable to use R2 because R1 is often reserved as the fault contact.
It is possible to control a mechanical brake in two different ways on the ATV31 / 312 / 320 drive using a relay output:
Please note that for the ATV320 drives, the menu structure has changed slightly and first you must access the FULL menu as follows:
RDY > CONF > FULL
Once in the FULL menu, you will see the SIN (Simply start) menu, but if you scroll from here you will find the same menu as the ATV31 / 312 drives.
For Horizontal movements with low load
I/O menu => r2 = FtA: Frequency threshold reached
Set menu => Ftd = 0.5 Hz: Ftd is the motor frequency threshold above which the relay contact closes
On starting, the R2 contact is open (brake engaged).
At the speed of 0.5 Hz, the R2 contact closes and remains closed as long as the speed stays above 0.5 Hz.
Vertical hoisting movement with obligation to brake the load
CTL menu => LAC = L2 (enable L2 by pressing and holding down Enter for 2 seconds)
FUN menu => BLC => BLC = R2
FUN menu => BLC => BRL = Brake release frequency: To be set to a value other than 0 (a few Hz is enough, between 1 and 3 depending on the application)
FUN menu => BLC => IBR = Brake release current threshold: To be set to at least the nominal current value indicated on the motor rating plate
FUN menu => BLC => BRT = Brake release time: To be set to the brake mechanical release time value (see specification provided by the brake manufacturer)
FUN menu => BLC => LSP = Low speed. To be set if the customer wishes to have one
FUN menu => BLC => BEN = Brake engage threshold: To be set between 0 and LSP depending on the application (if LSP other than 0)
FUN menu => BLC => BET = Brake engage time: To be set to the brake mechanical engage time value (see specification provided by the brake manufacturer)
FUN menu => BLC => BIP = Brake release pulse: Used for improved management of very high torque on starting, whether for upward or downward movement.
The pulse is always in the up direction (LI1 run forward)
This function is also used if the customer has a safety rack as well as the brake, to lift the rack locking catch.
After adjusting the basic settings, if the load slips on start up, increase the value in IBR
If load slipping occurs on stopping, decrease the BET value and an increase IBR may also be required
In the case of hoisting or position control, the Auto-tuning operation is essential.
This means reading the information on the motor rating plate and copying it into the drive DRC parameters, then launching the Tune or auto-tuning process. To carry out the auto tune the motor must be connected to the drive (output contactor active) and the LI1 or LI2 run command must be disabled.
The information required to be entered in to the DRC menu before an auto tune is carried out is as follows:
drC menu => UnS = Nominal voltage indicated on motor rating plate
FrS = Nominal frequency indicated on the motor rating plate
nCr = Nominal current indicated on the motor rating plate
nSP = Nominal slip indicated on the motor rating plate
COS = Motor power factor indicated on the motor rating plate
Set the parameter tUn = YES: Confirm by pressing the ENT key for at least 2 seconds If the auto-tuning operation is successful, tUn changes to Done.
If the auto tune does not complete then the display will show TNF (auto tune failed).
Applications that require brake control in a hoisting application often need a hoisting resistor fitting to the drive.
The electrical characteristics of the relays R1 and R2 relay contacts are as follows:
on a resistive load are 5 A for 250 VAC or 30 VDC
and on an inductive load (cos phi = 0.4 and L/R = 7 ms) are 2 A at 250 VAC,
they are inadequate for direct power supply of most mechanical brake coils, whose supply voltage alone is normally 400 VAC: you need to relay them using an LC1K or LC1D contactor.