I was playing around with my Model 5 today. My wife got me a new angle grinder for Christmas, so I fitted it with a thick rubber backing pad and used it to spin up my siren. It's the loudest it has ever been since I've owned it! While spinning it up, I noticed that it has a fast wind down compared to other privately-owned Model 5s I've seen on YouTube. I know that one reason is that it was about 35 degrees F outside when I spun it up, so the grease was thick. Even in the summer, however, it still has a faster wind down than other units.
The siren's motor has two grease ports: one where the rotor shaft meets the motor, and one at the tail end of the motor. They look like the type where you screw them in to force grease into the motor. Does anyone know how to refresh the grease in a motor like this? Will it involve a complete motor teardown? I don't think bearings are a problem as there is no lateral play with the motor shaft.
If a motor teardown is needed, I would be interested in re-motoring the siren to something that can run on single-phase power, probably 240 VAC. Has anyone done this with a Model 5?