high current dummy load,?

Moderators: grovkillen, Stuntteam, TD-er

Post Reply
Message
Author
User avatar
uxhamby
Normal user
Posts: 132
Joined: 29 Dec 2016, 18:13
Location: Toronto Canada

high current dummy load,?

#1 Post by uxhamby » 27 Feb 2021, 03:46

Hi,

I have several esp's, which operate table lamps, via a physical electro magnetic relay. Lamps are 120v ac. Relays are esp01 relay board ones from ebay and the like.

All works fine, except once I changed from incandescent bulbs to LED bulbs, I began to have trouble with the LED bulb's not always being at full brilliance.

I have played around and convinced myself that the trouble is that the <10W LED bulbs just don't draw enough current, to keep the relay contacts clean.

When an LED lamp is only part lit, if I plug a 60W incandescent lamp in parallel with it, both are instantly at full brilliance, as soon as the incandescent lights. I deduce that the increased current drawn by the incandescent, instantly burns thru whatever shyte was on the contacts.

I am thinking, I'd like to build in a high current dummy load, to put in place of the 60W bulb and which would switch itself out of the circuit after an initial few seconds, to automate this contact cleaning process each turn on cycle. (of course relays with mercury wetted contacts would probably work too but seems excessive, likely expensive and hazardous) (of course I used to have a couple of mercury wetted relays, from my old dad's collection, but turned them in at the local hazardous waste facility, when I cleaned out his place, thinking I'd never have need of such a thing. D'oh!)

I have tried solid state relays but don't favour that as a solution.

Before I go to trouble of building such a switchable dummy load however, it occurs to me to wonder, do such things already exist on the market for any reasonable amount of $ ? I don't see much with Googling around.

Thoughts ?

Cheers,

Brian H.

User avatar
Ath
Normal user
Posts: 3419
Joined: 10 Jun 2018, 12:06
Location: NL

Re: high current dummy load,?

#2 Post by Ath » 27 Feb 2021, 09:49

I'd opt for better quality relays, as in my experience, not all Chinese hardware is good quality :shock:
/Ton (PayPal.me)

TD-er
Core team member
Posts: 8643
Joined: 01 Sep 2017, 22:13
Location: the Netherlands
Contact:

Re: high current dummy load,?

#3 Post by TD-er » 27 Feb 2021, 11:12

I don't really understand why the relay can't get a good contact on low power consumption devices.
The only thing I can imagine is that the power factor of those LED lamps is so bad that it draws the highest currents at lower voltage during the sine period.
This may cause some arcing when disconnecting it, thus damaging the relay contacts.

I do know that in the past in large (factory) halls they added a capacitor to half of the tube light armatures to compensate for the bad power factor of those early days TL ballast units.

Maybe that can be helpful here too?
I don't have a scematic at hand here, but maybe this can be a starting point for your search?

User avatar
uxhamby
Normal user
Posts: 132
Joined: 29 Dec 2016, 18:13
Location: Toronto Canada

Re: high current dummy load,?

#4 Post by uxhamby » 27 Feb 2021, 18:00

better quality relays
Yes, this has occurred to me, but the actual objective here is amusing myself during lockdown, so I consider all kinds of crazy plans.


Brian H.

Post Reply

Who is online

Users browsing this forum: No registered users and 20 guests