Capacitor purpose

[jtjgvle]

Can someone explain just for my knowledge what the capacitors actually do? I discovered (by accident) that the bed powers up and seems to run just fine without the capacitors connected. I know capacitors store an electric charge so I thought they helped the lamps start.

(Sonnenbraune Wolf System 524e)

[Tony Randall]

Your capacitors are designed to absorb the excess power that your ballasts do not use. It is important not to run your bed without them because you can damage your ballasts and the lamps (to much power to them).

[jtjgvle]

Thanks Tony!

[scub]

I am quite surprised it didn't blow the breaker running wihtout them...do amperage readings at panel on that line with them and then without and you will find out why they are there.

[unity]

And here I thought that capacitors even out the electrical flow to prevent peaks and dips.

[engfant]

It is.

[jtjgvle]

As soon as I realized the wire had come off I reconnected it. I just wondered exactly what they were supposed to do since the bed seemingly came right on without them. Lots of good knowledge thanks guys. I'm not new to working with electricity but I am new to working on a tanning bed.

[parrot head]

I've had a couple of bad capacitors in my Sun capsule stand up. The lamps wouldn't light, they just flickered. I fould out one thing though; those bed capacitors so hold the voltage when they are disconnected. I got a good jolt when I touched both contacts.

[Brian Oshman]

Capacitors create a phase shift in the voltage vs. the current. This reduces the amount of current that the unit will draw as the voltage and the current waveform are shifted out of phase of each other by 90º so that during the cycle when the voltage is high the current is low and when the current is high the voltage is low.

Removing the capacitors will raise the current draw and the unit will trip the breaker.

Parrot Head, on Suncapsules the capacitors are wired in a lead/lag configuration. This is where there is a capacitor wired in series with every other ballast. This allows half the lamps to be at full power then the other half as the phase shift happens to half the laps at a different time then the other half still effectively reducing the current draw.



The standard setup in most beds are connected in parallel to the line voltage. This as explained above creates the Volt/Amp phase shift over all of the lamps at the same time so all the lamps are full or half power through the cycle. Cycle meaning electrical cycle of AC power.



If you take a picture of a Suncapsule while it is running the camera's scan rate will see the cycle and you will see in the picture that every other lamp looks dark. This is because the voltage is ramping up and down as all line voltage does 60 times a second.

On beds that are the standard line cap setup you cannot see this as all of the lamps are ramping up and down at the same time. You can see it with three phase beds as the lamps will be broken up over three phases so one bank may look brighter in the picture then another or Suckdash beds where the top is on one phase ond the bottom is on the other. (going off topic here but just explaining what you may have noticed in pictures and why)

[engfant]

brilliant!