LED light on dril press flickers

[The Cobbler]

Finally got around to replacing the broken Edison base lamp socket in my drill press. it has been broken for as long as I've had the drill.
Decide to put in a GU10 led pot light type bulb.
when I turn on the drill press, the lamp dies for a split second. I get that part. what has me stumped is when I turn off the motor, if the lamp is on, most of the time it dies for a split second too .
what could cause that?

 

[Paul_The_Builder]

The drill press motor probably has a single phase induction motor with a centrifugal switch to activate the "starting coil", which is phase shifted using a starting capacitor to get the motor spinning. This centrifugal switch is on when the motor is spinning at low RPM, and turns off once it gets spinning near the regular running RPM. You can probably physically hear the centrifugal switch release and the motor start spinning down quicker when you turn the motor off.

When the centrifugal switch is activated and the starting coil is connected to the input, the capacitor will phase shift the voltage/current, which will wreck havoc on the internal circuitry of the LED bulb, which probably uses a simple "capacitive dropper" style circuit to create the low voltage DC circuit that powers the LEDs.

That's a lot of gobbledy-gook, but basically at low RPM (both when the motor is spinning up and spinning down) the starting capacitor screws with the LED bulb circuitry.

More expensive bulbs will probably not have this same behavior, but just depends on the type of circuit the bulb uses.

I have a PAR 20 LED bulb on my drill press, which also has a centrifugal start circuit switch, and haven't noticed it dim or cutout.

That's my best guess, anyway.

 

[nadogail]

IMHO, Another argument for the halogen lamp in my drillpress

 

[dogdog]

Might be something to do with the cheap LED driver it has on the GU10 Lamps... some of them are just capacitor droppers

(you can search bigclives utube videos he have few tear down and explanations).

The E26 base bulbs from a known manufacture have better drivers, simply because of more room to fit those electronics.

or switch back the halogen bulbs if you decided to keep GU10 base.