12 Volt Timer

Motor City Today: GM announcing second-quarter earnings this morning

Whatever General Motors’ second-quarter earnings announcement holds today, don’t expect it to approach the excitement of last year’s Q2 results.

Last August, GM was gearing up to go public in the fall, and the automaker’s earnings announcement kicked off the company’s sales pitch to investors. But when GM began its earnings call Aug. 12, an official promised a special announcement from then-CEO Ed Whitacre.

Midway through the question-and-answer session, Whitacre’s Texan drawl cut in:

“Results like these make it clear that the new GM is on the right track,” he said. “It gives me a lot of confidence to begin transitioning—“

My notes from that day don’t finish that quote, as we at the Free Press rushed to publish the news: Whitacre was stepping down after eight months, and telecommunications’ and private equity’s Dan Akerson would become the automaker’s fourth CEO in 17 months.

Whitacre was expected to be a short-timer. But not that short.

A year later, GM has gone public, posted five straight quarterly profits and launched the Chevrolet Volt electric car. The automaker has had missteps and turmoil, too, including stuggles to make money in its European region and shake-ups of key management positions. But Akerson is still there – and vows to be for a few more years.

I want to automatically open and close a door using a Linear ...

I want to hook up a 12 volt linear actuator to a door hooked to a 110 volt timer with a plug on the bottom so when the timer turns the power on the plug will energize and the LA will open the door, and when the next set of pins on the timer come around it powers the plug again sending power to the LA again to close it, i obviously have to power the LA with a 110 v AC to 12 v dc converter, and most of the Linear Actuators have internal limit switches, so how can i revers the LA? Or do i need an AC Linear Actuator? The timer simply powers the plug on the bottom of it when the tab comes around and the next tab will be set to turn it off, in other words open in the morning and close at night, im thinking i need some switch with relays? any help would be apreciated. Ok, after looking at options in Grainger I got it,
So when the timer throws 110 v to the power supply that will thro 24 volt DC to a switching relay (every time power is interupted the relay switches contacs) so when the timer comes on it will retract the Linear Actuator and the limit will stop it, and then the timer will kick power on again thru the power supply switching contacs in the relay reversing polarity to the Linear Actuator
Grainger Alternating relay # 6CVF2 $24.00 bucks.

Thanks Guys,

Rob Reversing: If it's a DC motor, you generally just reverse the direction in which voltage is applied to it.

Having it start in alternating directions: Since power is off between the activations, the only "memory" you have in the system itself is the door position. But that's enough, with limit switches. Use one of the limit switches to control a DPTT relay (or a DPDT relay and a SPST relay). The relay should be set up so that one of the circuits it controls is a circuit that keeps it energized, so it acts as a latch (once on, always on until power is removed). The other pair of DPDT contacts is used like a DPDT switch to swap the connection on the motors -- wen energized, the relay causes the motor to run one direction, when not energized, the motor runs the other direction. Finally, take an input -- off one of the existing limit switches, or off a new switch you mount for the purpose -- which is also wired to power the relay's coil; this causes the relay to start up powered when power is applied _only_ when the door is pressed against that switch.

Should be easy enough to use those hints and turn them into a working system...

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