Danfoss VLT AQUA Drive Operating Instructions Manual page 74

8. How to programme the frequency converter
3-41 Ramp 1 Ramp up Time
Range:
*
10 s [1 - 3600 s]
8
3-42 Ramp 1 Ramp Down Time
Range:
*
20 s [1 - 3600 s]
3-84 Initial Ramp Time
Range:
*
0(off) [0(off) – 60s]
3-85 Check Valve Ramp Time
Range:
*
0(off) [0(off) – 60s]
3-86 Check Valve Ramp End Speed [RPM]
Range:
Motor Speed Low Limit
Speed Low Limit]
3-87 Check Valve Ramp End Speed [Hz]
Range:
Motor Speed Low Limit
Speed Low Limit]
74
Function:
Enter the ramp-up time, i.e. the acceleration time from 0 RPM to the rated motor speed n
a ramp-up time such that the output current does not exceed the current limit in par. 4-18 during ramping. See
ramp-down time in par. 3-42.
tacc
par .3 − 41 =
See drawing above!
Function:
Enter the ramp-down time, i.e. the deceleration time from the rated motor speed n
Choose a ramp-down time such that no over-voltage arises in the inverter due to regenerative operation of the
motor, and such that the generated current does not exceed the current limit set in par. 4-18. See ramp-up time
in par. 3-41.
tdec
par
.3 − 42 =
Function:
Enter the initial ramp up time from 0rpm to minimum reference. Some pump applications have a requirement
for different ramp rates when operating below the motor speed low limit. Initial ramp can be used as a faster
ramp rate to quickly bring the up to speed from stopped to prevent damage to its thrust bearings. When P3-84
is different from 0s the initial ramp time will be used instead of the existing Ramp Up Time (P3-41 or P3-51).
Function:
To control the Check Valve closure to prevent water hammering this parameter can be used to set a ramp down
time from motor speed low limit to Check Valve Ramp End Speed (P3-86 or P3-87) When P3-85 is different from
0.00 the Check valve Ramp Time is in effect and will be used to ramp down the speed from motor speed low
limit to the Check Valve stop speed set in P3-86 or P3-87.
Function:
* Set the speed in RPM below motor speed low limit where the Check Valve Ramp Time will no longer be used.
[0 – Motor
Function:
* Set the speed in Hz below motor speed low limit where the Check Valve Ramp Time will no longer be used.
[0 – Motor
MG.20.M4.02 - VLT
nnorm par
× .1 − 25
s
ref rpm
Δ
nnorm par
× .1 − 25
s
ref rpm
Δ
®
is a registered Danfoss trademark
®
VLT AQUA Drive
Operating Instructions
(par. 1-25). Choose
M,N
(par. 1-25) to 0 RPM.
M,N