Duty Assist
The Duty-Assist control is an effective method of controlling
multiple pumps or fans in parallel to maintain the required process
demand. Pumps and fans are often used in parallel banks to avoid
motor overload, guarantee security of supply through system
redundancy, reduce running costs due to system load cycles, and
provide a wide range of control and flexibility.
The system consists of a ‘Duty’ Drive and assist starters.The
assist starters can be of any type, (e.g, Contactor, StarDelta,
Auto-Transformer, Soft Starter or Inverter); the choice is
dependent on the system limits.The Duty drive can control one
dedicated motor (Fixed Duty), or with additional external
switchgear could be selected to control other motors within the
parallel configuration (Flexible Duty).
Standard Features
- Fixed Duty Motor – up to 4 Assist starters can be
controlled
- Flexible Duty Selection – up to 3 Assist starters can be
controlled
- Assist or Duty selection by Runtime (to ensure each pump/fan is
equal used) or a set sequence
- Automatic reselection requested assist fails to start
- Local/Remote: Digital control from Unidrive terminal I/O or via
fieldbus
- Standalone or system configurable
- Set-points and feedback can be derived as direct analog signals
or by fieldbus
More Features
- Auto-changeover to ensure starters are not continually running
for long periods of time
- Assists number of starts per hour protection (selectable)
- Assist Override delay to react to peak demands
(selectable)
- All data entry for set-up in engineering units
Locate your nearest Drive
Centre or Reseller