Danfoss VLT AQUA Drive FC 202 Operating Manual page 94

Operating Guide | VLT® AQUA Drive FC 202
• The CAN motor has a stainless steel can between the rotor and stator that contains a larger and a more magnetic resistant air-gap
than on a normal motor. This weaker field results in the motor being designed with a higher rated current than a normal motor
with similar rated power. The special CAN motor is used because of the wet installation conditions. Design the system according to
output current to be able to run the motor at nominal power.
• The pump contains thrust bearings that are damaged when running below minimum speed, which is normally 30 Hz.
• The motor reactance is nonlinear in submersible pump motors and, therefore, automatic motor adaption (AMA) may not be
possible. Normally, submersible pumps are operated with long motor cables that help eliminate the nonlinear motor reactance
and enable the drive to perform AMA. If AMA fails, the motor data can be set from parameter group 1-3* Adv. Motor Data (see the
motor datasheet). If AMA has succeeded, the drive compensates for the voltage drop in the long motor cables. If the advanced
motor data are set manually, the length of the motor cable must be considered to optimize system performance.
• It is important that the system is operated with a minimum of wear and tear on the pump and motor. A Danfoss sine-wave filter can
lower the motor insulation stress and increase lifetime (check actual motor insulation and the drive dU/dt specification). Most
manufacturers of submersible pumps require the use of output filters.
• EMC performance can be difficult to achieve because the special pump cable, which is able to withstand the wet conditions in the
well, is normally unshielded. A solution could be to use a shielded cable above the well, and to attach the shield to the steel well
pipe. A sine-wave filter also reduces the EMI from unshielded motor cables.
To prevent damage to the thrust bearings of the pump, and to ensure sufficient motor cooling as quickly as possible, it is important to
ramp the pump from stop to minimum speed as quick as possible. Most submersible pump manufacturers recommend that the pump
ramps to minimum speed (30 Hz) in maximum 2–3 s. The VLT
applications. The initial and final ramps are 2 individual ramps, where initial ramp, if enabled, ramps the motor from stop to minimum
speed and automatically switches to normal ramp, when minimum speed is reached. Final ramp does the opposite from minimum
speed to stop in a stop situation. Consider also enabling advanced minimum speed monitoring.
To achieve extra pump protection, use the dry-run detection function. For more information, see the programming guide.
Pipe-fill mode can be enabled to prevent water hammering. The VLT
up the pressure slowly with a user-specified rate (units/second). If enabled, the drive enters pipe-fill mode when it reaches minimum
speed after start-up. The pressure is slowly ramped up until it reaches a user-specified filled setpoint, where the drive automatically
disables pipe fill mode and continues in normal closed-loop operation.
L1 L2 L3 Ground
Mains
Ground
Illustration 43: Wiring for Submersible Pump Application
Set the analog input 2, (terminal 54) format to mA (switch 202).
92 | Danfoss A/S © 2020.01
U V W 12 18 27
Start
Stop
M
®
AQUA Drive FC 202 is designed with initial and final ramp for these
®
drive can fill the vertical pipes using the PID controller to ramp
13 54
2 wire 4-20 mA
Pressure
transmitter
N O T I C E
Wiring Configuration Examples
AQ275652274277en-000101 / 130R0708