Summary: Unipower load monitors protect pumps by measuring true motor power (kW) rather than current alone, allowing early detection of dry running, cavitation, dead head conditions, loss of prime and blocked impellers.
Charter Controls is the UK Manufacturer's Agent for the Unipower range, supplying load monitoring solutions for pump protection, process equipment and industrial machinery. Products are available from UK stock with next-day delivery.
View the full Unipower load monitor range
The Products
Unipower HPL500: Fixed-Speed Pump Duty
The HPL500 is the industry-standard load monitor for three-phase fixed-speed pump applications. It mounts on a standard 35 mm DIN rail inside the motor control panel and requires no wet-side sensors or additional wiring into the pump casing.
Key specification:
- Measures true three-phase motor power (kW)
- Two independently programmable relay outputs: minimum-power trip for dry run, loss of prime and dead head; maximum-power trip for blockage and overload
- Configurable start delay prevents nuisance tripping on motor inrush
- RS-485 Modbus RTU as standard
- Isolated 0/4-20 mA analogue output, scalable for closed-loop control
- Direct measurement up to 40 A without external current transformers
- Supply range 100 to 575 V
Unipower HPL500MB - buy or enquire
Unipower APM382: Variable Frequency Drive Applications
The APM382 is the correct specification where a variable frequency drive controls the pump speed. It reads PWM waveforms from 10 Hz to 1 kHz, tracks asymmetric load at variable speed, and includes a configurable shock-load trip for blockage and ragging events.
APM382 - view product or enquire
The Full Unipower Range
Charter Controls supports the complete Unipower load monitor family, including transducers, relay-output monitors, and analogue-output variants for conveyors, fans, screens, and process equipment as well as pumps.
Full Unipower range
Building a Complete Pump Station Protection System
The HPL500 and APM382 integrate directly with the rest of the Charter Controls range for a complete unmanned pump station specification.
- Telemetry: The WECON V-BOX H-AG 4G IIoT gateway connects to the load monitor via Modbus RTU and sends fault alerts to SCADA or directly to the operations team. No PSTN line required.
- Drive: The Veichi AC310 vector-control drive handles variable-speed pump duty from fractional kW to 110 kW, with built-in PID and RS-485 Modbus.
- Control logic: The GIC Genie Pro smart relay handles pump sequencing, level control, and alarm outputs within the same panel footprint.
One account at Charter Controls covers the full panel specification. All products in stock, next-day UK delivery.
Why Charter Controls
Charter Controls is the UK distributor for Unipower, holding stock of the full range for next-day delivery. Our technical team can advise on product selection for your specific pump type, motor rating, and panel configuration. We supply panel builders, OEMs, and water industry contractors across the UK.
Call 01424 850660, email enquiries@charter-controls.com, or use the contact form below.
Contact Charter Controls for Unipower specification support
FAQ
What Unipower load monitor should I specify for a fixed-speed centrifugal pump?
The HPL500 is the standard specification for fixed-speed three-phase pump applications. It provides dry run protection, overload trips, Modbus connectivity, and analogue output from a single DIN rail unit.
Which Unipower load monitor is suitable for use with a variable frequency drive?
The APM382 is designed for VFD applications. It reads PWM waveforms from 10 Hz to 1 kHz and includes a shock-load trip for blockage events at variable speed.
Do Unipower load monitors require wet-side sensors or flow instrumentation?
No. The motor acts as its own load sensor. The HPL500 and APM382 connect to the motor supply conductors inside the panel. No wet-side sensors, no additional wiring into the pump casing.
Are Unipower load monitors available for next-day delivery in the UK?
Yes. Charter Controls holds UK stock of the HPL500, APM382, and the full Unipower range. Call 01424 850660 or contact us online for availability and pricing.
Can I integrate a Unipower load monitor with SCADA or a remote monitoring system?
Yes. The HPL500 and APM382 both include RS-485 Modbus RTU as standard. The WECON V-BOX H-AG IIoT gateway connects directly via Modbus and provides 4G cellular telemetry for remote alarm and data logging.