POMPANO BEACH, Fla. – Oct. 12, 2009 – Dometic Marine has introduced a single-phase compressor motor startup control that reduces the startup current spike by up to 65 percent.
A current spike will occur whenever an air conditioning system cycles on, possibly causing brownouts, flickering lights, and tripped circuit breakers. In extreme cases, these current spikes can cause the generator output voltage to momentarily reduce or even shut down. When this happens, the air conditioning compressor can stall and fail to start. Over time, these failed startup attempts can cause damage to the compressor.
The SmartStart™ control is being offered with Dometic’s Cruisair and Marine Air boat air conditioning systems for OEM boatbuilders and for aftermarket retrofit.
“On average, typical single-phase soft-start products reduce startup surge by 20-40 percent. By reducing startup surge by as much as 65 percent, this gentler method of handling a power surge can mean the difference between boatowners keeping the generator they already have, or investing thousands of dollars on a larger generator,” said Frank Marciano, president, Dometic Marine.
Once running, a compressor has a much lower, steady amp draw. It is the initial locked-rotor amps needed to start the system that create high current surges which can adversely affect the operation of an overstrained generator. Many generators and shore power connections have sufficient power to run one or more air conditioning units, but may not have sufficient power to start one or more units, especially if units are already running.
John Poole, of Poole Refrigeration, conducted field trials of the SmartStart control aboard a 37-foot Nordic Tug. “The generator’s control circuit would trip and stop the generator due to the inrush current of the boat’s heat pump,” he reported. “The SmartStart control reduced that inrush current so the generator would continue to run. We started with an inrush of 77 amps and finished with only 20 amps. It is a great solution to our problem.”
“This is a cost-effective solution to resolving the problem where a generator or shore power source is not adequate to start one or more air conditioners,” added Poole. “Before the SmartStart, the only alternatives would be replacing the generator or the shore power system with one of larger capacity, or replacing all the single-phase air conditioner compressors with three-phase models and adding a variable-speed frequency drive to each one. All of which are much more expensive than the new Dometic SmartStart.”
The SmartStart control measures 5 inches by 3 inches by 2 inches (127mm by 76mm by 51mm), and is available in three voltage/frequency varieties, making it easy to install on virtually any existing boat air conditioner. The 15-ounce (0.43kg) control wires directly into the air conditioning system’s electrical box. If space does not permit, the control can also be mounted outside the electrical box since it has a drip-proof enclosure.