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lamp dimmer on LED power cord??

1K views 8 replies 6 participants last post by  jeffkrol 
#1 · (Edited)
Do people think you can put an inline lamp dimmer on an LED light? For that matter, on the power cord of a filter to reduce the flow? I'm interested in doing the filter because mine has too much flow. I'd like to know if people think it's safe, too.

This hardware uses a low wattage, 3W x numer of LEDs, not much on the impeller of a filter, and a lamp dimmer works on straight wattage from the cord, say on a filter.

An in-line lamp dimmer interrupts the power cord and has a variable voltage switch that reduces the voltage and I would think slow the impeller of a filter, just like it would dim a lamp.

Thanks for the advice.
 
#2 ·
You should never use a dimmer on a electric motor! The motor will very likely be harmed by doing so. If you want to reduce the flow through your filter you can safely restrict the output of that filter with a valve. The pumps used in filters don't generate much pressure at all, so restricting the flow from them doesn't result in the pump being forced to build up a big pressure. Those pumps just move water, but at a low pressure. When you restrict the line the water flows through, all that happens is that the pump moves less water.

Dimmers that work with incandescent lighting don't work at all with LED lights. You will probably just shut off a LED light if you try to use a dimmer on it.
 
#3 ·
Lamp Dimmers do not work on LED's or Motors so your premise is entirely flawed.

exception:Unless the LED was specifically designed to do so, like incandescent replacements that screw into traditional lighting.

a FAN SPEED CONTROLLER designed for motors MIGHT work on a pump, but more than likely will simply burn your pump up because they typically make fans emit odd noises at partial speed.
 
#5 ·
I don't think fan speed controllers will work on mag drive aquarium pumps. They're different than the types of motors used in ceiling fans, etc.

LED drivers have to be designed to be dimmable, otherwise they won't be able to dim no matter what. They have somewhat complicated circuitry and unless they're designed to be dimmable, they're designed to keep a constant current regardless of voltage fluctuations.
 
#7 ·
LED drivers have to be designed to be dimmable, otherwise they won't be able to dim no matter what. They have somewhat complicated circuitry and unless they're designed to be dimmable, they're designed to keep a constant current regardless of voltage fluctuations.
well yes and no.. All those LED strips you see are run on constant voltage..
A switching power suppy x number of led's whos V(f) is under the ps voltage and a current limiting resistor..
to "dim" them all you need is a chopping curcuit composed of simple "parts"..
By varying the voltage timing you "dim" the LED .. 12v at 50% of the time is dim..
nothing more than a high speed switching circuit using say a timing chip or mosfet..

Once you get into self contained AC driven (initially) LED "bulbs" then things get more complicated..

Simple LED dimmer for 12v constant voltage LED's

http://www.reuk.co.uk/LED-Dimmer-Circuit.htm
http://www.electroschematics.com/9730/high-power-led-dimmer/
 
#6 ·
EVERYTHING depends on the motor type:
There are several types of single-phase "AC motors." Some, like the universal motor wth brushes are relatively easy to control. The capacitor-start and split-phase can be very difficult to control, and when controlled, they lose a great part of their torque. The aquarium pump is possibly a synchronous motor, in which case you should be able to control it with frequency, not pwm.

The place to start is to determine what type of AC motor you have. Search on synchronous, split-phase. and capacitor start motor to see if any match what you have. John
http://forum.allaboutcircuits.com/threads/ac-motor-speed-controller.9753/

As to the LED's it all depends on how they are driven..
Constant voltage LEd's can be dimmed using PWM to "chop" the voltage.. not change it.. nor change the current..
constant current LEd's usuallly have dimming "built in"

and ect.. ect.. many variations including current control

You need to know more specifics on any setup to determine if any of this is possible..

This will control some AC motors but is useless for LED
http://www.rakuten.com/prod/dart-co...o&adid=29963&gclid=COuvyPeap8UCFZRgfgodBCcA7w

https://www.anaheimautomation.com/manuals/forms/ac-motor-guide.php
 
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