# Size factor of capacitors now and then?

I have a motor at home, it's a soviet era motor. It's connected to what seems to be a capacitor.

The setup pretty much look like the following one except the red box is much larger than the one on the picture and I can't see the markings. The one on the picture is 2uF 10% for 400v.

I was wondering if there was a particular reason why the capacitor is so big. If it's just that now capacitors for the same specs can be much smaller than the ones in the 70s.

Also I don't really understand the wiring of the motor. Mine is wired pretty much the same way except I have a switch that lets me change the rotation direction. I can't tell much for now as I'd have to dismount everything to access the readings to get a better idea. What I can tell is that this is a 127v AC motor. Here are the markings:

127v 30hz 6w

To my understanding, the capacitor is used to somewhat limit the current to something around 127v. So tecnically, I could replace the beefy capacitor by one of same value that I gather from broken fluorescent/led lamps?

The pictures are taken from this article: How to connect a 127v motor to 220v (Russian)

• To my understanding, the capacitor is used to somewhat limit the current to something around 127v Current is measured in Amperes (A). Voltage is measured in Volts (V). Capacitors can not limit current and DC voltage. Anyways, the size of a capacitor is determined by its capacitance and rated voltage. Commented Feb 27, 2017 at 14:10
• It's an AC motor btw and I didn't meant "current" as in amperes but as in the normal way people use it. Like DC is direct current ans AC alternative current. Capacitor can be used to limit the current as it's AC and the capacitor should keep discharging every 50-60hz. Commented Feb 27, 2017 at 14:56
• Your dropping voltage, not current. But is the motor marked 127 V? If yes, then it's like you say a series capacitor to drop the voltage although highly load dependent and a fairly dangouros situation. It could also just be a normal 230 V motor and a capacitor connected in paralell for phase compensation. Commented Feb 27, 2017 at 16:11
• @winny yes, I just checked and it's really 127v 30hz 6W. Commented Feb 27, 2017 at 16:35
• Oh! Then series dropper. Terrible solution. Commented Feb 27, 2017 at 16:53