High Pressure Sodium and Metal Halide Lamp Control Gear

Micatron

SwiitchDim unit - the basic function is to dim or part night-switch street lighting loads.

It has four connections:

1 - Neutral

2 - Live

3 and 4 - The two output connections of a 10A changeover relay.

It is wired into the lighting circuit between the photocell and the ballast. When the photocell switches on at dusk, the microchip on board starts to record time. When the photocell switches off at dawn, the microchip records the length of night. On subsequent nights it can calculate Midnight (or any other part night time). The microchip can then be programmed to switch the relay between the two connectors (3 and 4) at any time of night.

This switching arrangement allows a multitude of energy saving applications on street lighting:

1. Dimming using a dual-tapped ballast.

A number of wire wound ballasts exist with two tappings. For example, some lanterns are fitted with a 50 Watt/70 Watt ballast. Connector 4 of the SwitchDim unit is wired to the 70 Watt tapping; connector 3 is wired to the 50 Watt tapping. When the photocell switches on at dusk, the output is to the 70 Watt tapping. At Midnight (or any other part night time), the relay can switch over to the 50 Watt tapping and dim the lamp. It can be changed back again at say 5am (or any other part night time) to the 70 Watt tapping. The photocell will switch off at dawn and the new length of night stored to calculate the next night's switching times.

2. Part Night Switching

If the ballast is wired using connector 4 only, the switch gives a part night output. This makes the switch ideal for retrofitting with anybody's control gear. It is wired between any standard all night photocell (one part, two part of minicell) and any wire wound ballast. It is a simple conversion to make the installation part night.

3. Dual Circuit Option

If a link wire is connected between connector 2 and 3, then an all night operation is available to connector 3 and a part night operation is on connector 4. This makes the switch ideal for applications such as switching Christmas lights (all night output for the street light; part night output for the Christmas lights); part night switching of a street light with an all night feed to associated signage, etc.

4. Switch Dim Option

Using a SwitchDim ballast (which has a momentary switch contact that will dim a compact fluorescent lamp in proportion to the length of time the contact is made), the microchip can be programmed to momentary switch at Midnight (or any other part night time) to dim the lamp. This can then be momentary switched again at say 5am (or any other part night time) to bring the lamp back to full brightness.

5. 0-10V Option

An option is available which will dim electronic ballasts with a DALI 0-10V input.

6. PIR Option

An option is available which interfaces with a PIR detector. The output will normally be set to dim and will step increase the light level when motion is detected by the PIR. It can be used in car parks; lighting bollards, etc.

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