569
Item nr.


SelectTime 1723528 Switching Clock

Energy saving pilot.


Data for SelectTime 1723528
ProductionUnknown, 2002.
CabinetPlastic. Size 7x12x3cm.
PowerAC230V, 800mW (now 52mW).

The Design

Mechanical switching clocks are useful for operating lights, computer modems, etc. Unfortunately, they use a lot more energy than necessary. The small motor operates with about 4mA of current on a small voltage (20 to 30V typically), and is fed from the mains through a ballast resistor. This unit has a ballast resistor of 47k, and to waste even more energy, this type also has a small LED operating through a 100k resistor. The unit consumes almost 1W continuously when OFF, and 1.5W when ON.

Obtained7/2022 from Kringloop De Bilt.
Condition9.
Value (est.)3,3€.

This Object

I routinely replace the ballast resistors by capacitors, to reduce the power consumption of the clock to about 0.1W. In the case of this SelectTime, I also cut the LED supply.

In November 2022, I replaced the ballast capacitors in all of my clocks by X2 types. After measurement of the old capacitors, I found that the 60nF ballast in my SelectTime, in use for about 3 years, had reduced to 31nF. Unfortunately, the X2 types are very sensitive to Senseo syndrome, and my clock stopped operating in August 2023. The 47n X2 capacitor had decreased to 24nF in just nine months! I installed a 33nF capacitor rated at 1000V. With this capacitor, the power consumption of the clock is just 52mW.


Part of Gerard's Radio Corner.
Generated by SiteBuilder on 26/2/2024 by Gerard (g.tel@uu.nl)