New 10KVA Uninterruptible Power Supply for Naval Applications from Gresham Power

Input is the ship’s standard 440V 3phase 60Hz supply. In normal operation, the rectifier float charges the battery while supplying the DC input to the inverter which then supplies the output. In the event of a failure of the input supply the battery seamlessly provides a stable output for the specified duration. The battery begins recharge as soon as the ship’s supply is restored.



Jake Moir, Managing Director of Gresham Power Electronics, comments. “Our new 10KVA UPS is a brand new, high-efficiency, compact design that meets the requirements of modern warships. Gresham has a long history of providing power conversion and distribution equipment to Navies around the world and with a number of new vessels in the planning stage as well as strong export demand; we are embarking on a major programme of product development to meet current and future warship power conversion and distribution needs.”



While as one would expect, the UPS is designed to meet a warships normal environmental requirements in terms of shock, vibration and EMC, the unit exceeds normal “below decks” standards with an ingress protection rating of IP54. This significantly increases possible applications and gives Naval architects more options in equipment location.



As well as standard ship’s supply of 440 volts alternative optional inputs of 115V or 230V can be accommodated. As a small business Gresham can be flexible to customers’ demands rather than offering a fixed range of equipment thus enabling the equipment to be configured to meet specific requirements rather than requiring system architecture to be changed to meet inflexible equipment specifications.



The UPS provides an output of 115V 1-phase at 60Hz and 10kVA, sinusoidal waveform of <2% THD with linear load and <5% non-linear load. Static voltage regulation ± 1%, dynamic voltage regulation ± 5% (100% load change) and frequency stability ± 0.1% and efficiency typically 90%

The Gresham 1RCQ10KA UPS is protected by an input circuit breaker and also has output short circuit and over current protection. Over voltage and over temperature trips are provided to afford general protection as well as battery cut off at the end of discharge and battery overvoltage protection.



Local controls and indicators include, supply ON/OFF selector switch, LED indicators for supply available, rectifier, battery, inverter and a liquid crystal display with scroll pushbuttons to view the parameters.



An RS232 interface gives remote indications of status/fault information plus the parameter values of supply voltage, supply current, output voltage, output current, battery voltage, battery charge/discharge current, temperature and battery capacity.



The 1RCQ10KA UPS is housed in a custom cabinet of fabricated mild steel folded and welded for strength. Overall dimensions are 1450 x 864 x695mm.



The equipment is deck mounted with top steadies. The unit weighs 375kg and lifting eyes are provided. Cable entry is through the top via a gland plate that can be drilled or punched as required. User connections are made to internal rail mounted and stud terminals.



In order to meet the IP54 rating cooling fans are positioned on the front of the equipment. Cool air is drawn in at the bottom and warm air exits at the top. Cooling fans for the power assembly are also fitted.



All internal wiring is low fire hazard cross linked polyolefin RADOX 125. An external M10 earth stud is located adjacent to the gland plate. Provision for fire extinguishing is made via a CO2 injection socket in both the equipment and battery cabinet.



The Gresham Power 1RCQ10KA UPS is designed to meet a shock requirement of a maximum vertical acceleration (half sine-wave pulse) of amplitude 117.7m/s2 (12g) and of duration 9ms (rise time to peak velocity) and 24ms (fall time to zero velocity). For installed shock levels in excess of this shock mounts should be fitted. The unit is designed to withstand shipboard vibration typically: 5 to 33Hz +/- 0.125mm hard mounted and has a noise rating of < 60dbA. @ 1m



The UPS is designed to comply with the requirements of Def Stan 59-41.Emissions and susceptibility (Below deck limits) and operates over an ambient temperature range of 0 to + 45ºC with relative humidity between 10% to 95% non-condensing. All internal PCBs have a conformal coating to protect against the effects of humidity.



The full Gresham Power Electronics Naval product range includes; Military grade UPS, Helicopter Start and servicing systems, Static Frequency Converters to 40kVA, Rectifiers and DC distribution systems with battery support and submarine battery chargers. As well as this scope of main equipment Gresham can also offer Motor Starters, Automatic Changeover Switches, through bulkhead Filter Boxes, Navigation Light Display and Control Panels. Distribution Panels, Weapons Panels and Ship to Shore Supply Boxes.