I bought a british warning siren made by Secomak, which has a motor rated for 240VAC/DC 3A @50Hz. I am confused on how to provide it power. Not only do I somehow have to provide it 240V (which would require at least a transformer given that US outlets are only 120V), but I've also been told US 240VAC power
The AC/DC rating indicates that the siren has a universal motor. That is essentially a DC motor with a commutator and brushes that is designed for use with either AC or DC. I believe that the starting current for a universal motor is less than for a regular AC motor. Even though one leg of UK 240 volts is grounded, I doubt that the frame of the siren is grounded. You can check that with a multimeter. At a minimum, you should have help from someone who knows how to use a multimeter. PS1 If I had the siren, I would probably connect it directly to a regular 120 volt outlet. If it has a universal motor, it should run at a lower speed, but not take too much current or anything. You should be able to check it out using just the two hot wires from a dryer outlet. You might be able to add a 15 or 20 amp 240 volt circuit to power it. A transformer large enough for it would be about half the size and weight of the motor. An auto-transformer would be a little smaller. With a rectifier and filter, you can get about 160 volts DC fro a 120 volt outlet. The motor will run a little faster at a given voltage with filtered DC, so 160 volts might be enough. PS2 I should have said that I doubt that the frame of the motor is connected to one of the power inputs. When you install the siren, you should connect the frame to the grounding conductor of the power system.
50Hz motor runs with 60Hz power result lost almost 1/3 of its original torque while running on 50Hz. Rotation from motor becomes slower.
