Sangamo timers

Steve · 26 Oct 2007

http://www.tlc-direct.co.uk/Images/Products/size_3/SGS254.JPG

Anyone ever known one of these go wonky?

I have one (at work) which switches off at around 6pm. But its on time is 4pm to 10:30pm. If I go and click its override, the lights stay off, then click again and they come back on! As if it was still on before. But it wasnt.

Its 4 years old tops. There are no other controls on this circuit (this is the fluorescent fascia lights, which run direct from the timer - there is a photocell, timer and contactor seperate for the carpark's sodium lighting)

ColJack · 26 Oct 2007

we had a similar problem at work about a month ago..

turns out that the timer runs a contactor through a photocell.. they had no idea and spent a day trying to figure it out..

so the photocell kept turning the lights off while they were trying to see which ones needed changing..

they'd press the overide and go outside but they'd switch off after 5 mins or so once the "settling" period of the photocell had gone..

you may have the same thing.. but the photocell wired backwards.. turning the lights off when it gets dark at about 6 ish..

RF Lighting · 26 Oct 2007

I would think it is unlikely to be the time switch. Sangamo clocks are about the best there is on the market.

ColJack · 26 Oct 2007

and about the most basic.. just a motor to turn the dial and then it's all mechanically switched contacts..

bernardgreen · 26 Oct 2007

The only time I saw a Sangamo go wrong was when the knob in the centre was loosened ( perhaps by someone trying to reset the time ) and the tappet arms were loose and had moved away from their original settings.

breezer · 26 Oct 2007

and dont forget the knob tightens the "wrong way"

ricicle · 26 Oct 2007

Didn't PE once run a competition to find the oldest working Sangamo timer in existence.IIRC they found one decades old (didn't check this though - not sure how long they have been around)

Steve · 26 Oct 2007

UPDATE! I went into the plant room again today, and the first time i clicked the override, there was a crackling and a longer-duration blue arc. I switched it a couple of times more, but it just did its brief small arc, and they stayed on until we vacated the premises at 10:10.

Are the contacts fooked? They switch about a kilowatt of fluorescent lighting.

This timer is the model with "day omit" on it (little dial behind the main one). It could be possible they have been tampered with and the lights aint coming on at all. Which way should the arrows be pointing? No days need omitting.

Spark123 · 26 Oct 2007

They point inwards to enable the day.

Steve · 1 Nov 2007

I FIXED IT!!!!!

For those that aren't familiar with sangamos, they consist of a dial with 4 arms, indicating the 4 switching times. under the arms are a small pin which knocks 2 levers underneath. The ON pins knock the ON lever, and the OFF arms knock the OFF lever. These levers engage and disengage a contact, which makes the circuit.

The pins under the arms are different lengths, due to them being fixed to the dial on top of one another. I noted on turning the dial that the evening ON pin was too short to reach its lever.

Someone in the past has put the arms on the dial in the wrong order, causing the evening ON arm to never engage the lever to switch the lights on.

Anyway I unplugged the timer, set it on the desk and took it to pieces (simple thumbscrew), compared the lengths of the pins to determine the best assembly order, and got it back together. Plugged it back in, turned it to evening ON, and low and behold, LIGHT!

Later on i happened to be stood outside when the lights came on. What a feeling.

securespark · 1 Nov 2007

breezer said:
and dont forget the knob tightens the "wrong way"

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Sangamo timers

breezer

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