Danfoss MCD3000 Series Manual page 18

2. On generator set supplies where a gradual
increase in current is required to allow greater
time for the generator set to respond to the
increased loading.
In this case make the following settings.
•
Set Parameter 2 Current Limit as desired.
•
Set Parameter 3 Current Ramp - Initial
Current to a lower level than the Current Limit.
•
Set Parameter 4 Current Ramp - Ramp Time
to achieve the desired gradual draw of start
current.
5 Soft Stop Ramp Time
Value:
0 - 100 second
Function:
Sets the time of the soft stop ramp. The soft stop
function extends motor deceleration time by ramping
down voltage supplied to the motor when a stop is
initiated.
Description of choice:
Set the ramp time to optimise stopping characteristics
for the load.
The MCD3000 soft stop function has two modes,
standard and enhanced pump control. The enhanced
pump control mode can offer superior performance in
some pumping applications. Refer Par. 17 Soft Stop
Profile.
ATTENTION
The MCD3000 soft stop function automatically
determines the step-down voltage setting, no
user adjustment is required.
ATTENTION
The Soft Stop and D.C.Brake functions cannot
be used together. Setting a soft stop ramp
time greater than 0 seconds causes Par. 18 D.C.Brake
- Brake Time to be set to 0 seconds and Par. 38 Relay
C - Function Assignment to be set to OFF.
= factory setting
18
MCD3000 Series
6
Value:
5 - 120 second
Function:
Calibrates the MCD3000 motor thermal model for the
connected motors thermal capacity. The Motor
Thermal Capacity is defined as the length of time the
motor can sustain Direct-On-Line current.
Description of choice:
The factory setting is adequate for most applications.
When setting the Motor Thermal Capacity two
approaches can be taken.
1. Set according to the Motor DOL time as shown
0 seconds (Off)
on the motor data sheet. This makes the full
thermal capacity of the connected motor available
for use. The motor will be allowed to operate up to
its maximum capability during start and when
subjected to operational overloads.
This is ideal when starting high inertia loads or for
applications such as Bandsaws that must ride
through high operating overloads.
Current. Actual motor DOL current can be accounted
for by using the following formula to calculate the value
of the Motor Thermal Capacity setting.
2. Set according to load requirements. While the
Motor Thermal Capacity can safely be set
according to the motor's published DOL time limit,
some load types do not need this capacity for
starting or riding through overloads while running.
In such circumstances setting the Motor Thermal
Capacity based on what the load requires will
provide an earlier warning of abnormal operation.
To set the Motor Thermal Capacity according to
load requirement, set MCD3000 display to read
motor temperature, run the load, stop and restart
the load while monitoring the calculated motor
temperature. The Motor Thermal Capacity setting
can be reduced until the temperature at the end of
a restart is approximately 80%.
Motor Thermal Capacity
ATTENTION
The MCD3000 assumes Direct-On-Line
current to be 600% of motor Full Load
MG.15.A2.22 – VLT is a registered Danfoss trademark
10 seconds