• Dimmers, Watts and Fuses
• Optics

Dimmers, Watts and Fuses

If you think of electricity (a flow of current through a wire) in terms of a water flow through a pipe, then voltage is the pressure of the pump driving the water through the pipe, current is the amount of water flowing and power is a measure of the work the water is able to do when it turns a turbine.

Power is voltage x current. Voltage is measured in Volts, and Current is measured in Amps.

Each lantern has a power rating in Watts.

For example, a Patt.123 Fresnel is 500W and a Cantata PC is 1200W.
The wattage refers to the amount of electricity needed to make the lamp light.
A brighter lamp needs more electricity.
Therefore, the Patt.123 has a lower power requirement (wattage) than the 1200W Cantata PC.

1000W = 1kW = 1 kilowatt

This is important information because the electrical supply into the building is limited, as is the power capability of the dimmers. Most dimmers in the UK are each rated at 10 Amps. This means that they can provide 10 Amps of electrical current before they overload and cause the fuse to blow.
It is difficult to see the link between Amps anything else until you see the following equation : Power (Watts) = Current (Amps) x Voltage (Volts)

Taking the Patt.123 Fresnel as an example; Power = 500W Voltage = 230V (this is more or less standard throughout Europe) so Current = 500W / 230V = 2.17 Amps.

This means that you could plug a Patt.123 into a 10 Amp dimmer and still have nearly 8 Amps left to play with before the dimmer became overloaded an blew a fuse.

Using another example, the Patt.743 Fresnel has a 1000W lamp; Current = 1000W / 230V = 4.3 Amps.

Therefore, the 743 is using just under half the dimmers' rated capacity of 10 Amps. This means that you could safely plug two of these 1000W lanterns into one dimmer without blowing the fuse.

Please note: it may be easier for you to remember that a 10A dimmer has a potential load of 230V x 10A = 2300W. As long as you keep under that wattage, you won't overload it.

Fuses

The Zero 88 Chilli Pro dimmer racks shown on the left contain twenty-four dimmers. Each dimmer has a MCB (miniature circuit breaker) protecting it, which is located in a panel at the right hand side of the dimmer rack. This circuit breaker is rated at 10 Amps. Any current over that level will cause the breaker to trip so that the dimmer circuitry and cabling doesn't get damaged. The dimmers are arranged so that the breaker on an individual circuit will blow before a circuit breaker trips on a whole dimmer rack. If a lamp blows on the rig, chances are that it will take out the dimmer circuit breaker when it blows. There is a high current briefly before the lamp expires which is sufficient to blow the fuse. It also follows that if a fuse has gone, its probable that the cause of that is the lamp blowing. If a fuse keeps blowing for no apparent reason, seek help - don't keep replacing it.

Remember :

At 240 Volts, the maximum load on each 10A dimmer is 2400W and 1000W = 4.16A
At 230 Volts, the maximum load on each 10A dimmer is 2300W and 1000W = 4.35A

(NB: The above figures apply in the UK and Europe - the USA uses 120 Volts)

Optics

FOCAL LENGTH

Every lens has a property called focal length.

The focal length is the point at which parallel rays from the sun will converge on passing through the lens. It follows that if a light source is placed at the focal point, the lens will produce parallel rays. If a light source is placed between the lens and the focal point, diverging beams will result. If a light source is placed beyond the focal point away from the lens, converging beams will result.

Under construction - more coming soon