Special functions
© KEB, 2012-10 COMBIVERT F5-A, -E, -H Page 7.15 - 17
7
To hold the cabin, the motor requires + rated torque .
For a fully loaded cabin, the load weighing setup provides a signal of 100%.
To hold the cabin, the motor requires + rated torque .
Let the signal from the load weighing setup be connected to AN2, which serves as the AUX-
input.
I.e.: a signal of 0% on AN2 shall produce a precontrol value of 100%
a signal of +100% on AN2 shall produce a precontrol value of -100%.
"AN2 offset X" (An.16) be equal to 0%, "AN2 lower limit" (An.18) = -100%, and "AN2 upper limit"
(An.19) = 100%
The formula for amplication and offset setting is then for AN2:
Output signal = "AN2 amplication" (An.15) * input signal + "AN2 offset Y" (An.17)
This gives, for "AN2 offset Y" = 100% and for "AN2 amplication" = -2
Operation without encoder
Since the settings range of the drive is limited during operation without encoder, no brake handling should be
used for SCL as well as for ASCL.
For SCL, parameters "premagnetizing time" (Pn.35) and "brake release time" (Pn.36) are used for the align-
ment of the motor with DC current (see chapter 7.6.3.4 SCL / standstill and starting phase)
7.15.5.5 V/F characteristic controlled operation
Start reference (Pn.37), stop reference (Pn.41)
In v/f-characteristic controlled operation, start and stop values must be set to hold the load in standstill respec-
tively, reach standstill after deceleration, in order that the brake can engage again.
The adjustable start/stop value stands in direct connection with the necessary holding torque. A preset value
can be obtained according to the following formula:
(synchronous speed– rated speed) x required holding torque
——————————————————————————————
Rated torque
Start- and, respectively,
stop value =
Based on these value, an adaption to the particular application must be made since other values, e.g., the
boost, also have an effect on the behaviour during load transfer.
Example: a 4-pole motor has a rated frequency of 50 Hz and a rated speed of 1460 rpm.
The synchronous speed of the motor thereby is = 1500 rpm and the slip speed is 1500 – 1460 = 60 rpm at rated
torque and nominal voltage.
The drive should be able to provide rated torque at brake release if a start value (Pn.37) of 60 rpm is preset.
Premagnetizing time (Pn.35)
So that a torque can be built up, the ux in the motor must have been built up. The motor is energized with
starting the premagnetizing time. This time must be long enough for the motor to build up its ux.
Depending on the motor, this time can be between approximately 100 ms (small power) and fractions of a se-
cond (motors with large power).
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