Jump to content


Help Support AussieHomeBrewer!

http://aussiehomebrewer.com/store/

Photo
- - - - -

Ssr Vs Mechanical Relays


  • Please log in to reply
9 replies to this topic

#1 Lilo

Lilo

    Mini Mash

  • Members
  • PipPipPipPipPipPip
  • 198 posts
  • Joined 03-June 07
  • Location:Brisbane

Posted 09 February 2010 - 08:49 PM

Most reading I can find on diff heating setups, people have selected SSR relays over Mech type.

I could understand if they were using cyclic control devices or the such where the heater is switched on/off quite frequently.

If using a basic Temp controller with a reasonable switching hysterisis, why not use Mech Relays instead??

Thoughts??? Am I missing something obvious ( Again )

:huh:

#2 Spartan 117

Spartan 117

    Beer God

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 538 posts
  • Joined 30-October 08
  • Location:Melbourne

Posted 09 February 2010 - 08:56 PM

If you're looking for a temp controller I recommend mashmasters one, cheap, easy to wire, user friendly and works really well. It's all ready to go all you need is an extension chord and you don't need to worry about wiring up relays or anything.

Not sure if this is the answer you're looking for, none the less hope it helps

Aaron

#3 Screwtop

Screwtop

    Inspectors Pocket Brewery

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 7,550 posts
  • Joined 08-September 05
  • Location:Queensland - Australia

Posted 09 February 2010 - 08:57 PM

Most reading I can find on diff heating setups, people have selected SSR relays over Mech type.

I could understand if they were using cyclic control devices or the such where the heater is switched on/off quite frequently.

If using a basic Temp controller with a reasonable switching hysterisis, why not use Mech Relays instead??

Thoughts??? Am I missing something obvious ( Again )

:huh:



Overkill for some applications, I use 240v 30A mech relays for beefing up the relay contacts of other devices and things like float switches etc.

Screwy

#4 Lilo

Lilo

    Mini Mash

  • Members
  • PipPipPipPipPipPip
  • 198 posts
  • Joined 03-June 07
  • Location:Brisbane

Posted 09 February 2010 - 09:20 PM

If you're looking for a temp controller I recommend mashmasters one, cheap, easy to wire, user friendly and works really well. It's all ready to go all you need is an extension chord and you don't need to worry about wiring up relays or anything.

Not sure if this is the answer you're looking for, none the less hope it helps

Aaron



Thanks Spartan

Not what I was after, I use 2*Mashmasters now and they are pretty good.

#5 Lilo

Lilo

    Mini Mash

  • Members
  • PipPipPipPipPipPip
  • 198 posts
  • Joined 03-June 07
  • Location:Brisbane

Posted 09 February 2010 - 09:23 PM

Overkill for some applications, I use 240v 30A mech relays for beefing up the relay contacts of other devices and things like float switches etc.

Screwy



Cheers Screwy,

Exactly as I concluded. SSRs are overkill for this application. Looks like you and I are in the minority. May be our Telco backgrounds gives us a sentimental attachement to Mecho devices


Cheers

#6 Screwtop

Screwtop

    Inspectors Pocket Brewery

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 7,550 posts
  • Joined 08-September 05
  • Location:Queensland - Australia

Posted 09 February 2010 - 09:25 PM

It's all ready to go all you need is an extension chord



Yeah Aaron but have you ever tried to get one in C Major :lol:

Couldn't resist, Cheers,

Screwy

#7 paulwolf350

paulwolf350

    Beer God

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 594 posts
  • Joined 12-July 08
  • Location:Rockhampton, Qld

Posted 09 February 2010 - 09:26 PM

Cheers Screwy,

Exactly as I concluded. SSRs are overkill for this application. Looks like you and I are in the minority. May be our Telco backgrounds gives us a sentimental attachement to Mecho devices


Cheers


My controller cuts in/out a couple of times a minute, i didnt want the clunking in/out when i was standing next to it for 3.5 hours

otherwise mechanical relays will do an excellent job

Paul

#8 Zizzle

Zizzle

    Beer God

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 1,013 posts
  • Joined 22-April 06
  • Location:Ridgway, Colorado

Posted 09 February 2010 - 09:30 PM

Well I have no problems with mechanical relays. The brewbot has a number of them.

Like you hint at, we deal with large thermal masses that change at around 1 degree/min max, so fast switching is usually not needed.

A lot of cheap relays are "only" rated for a ~100K cycles.

With an SSR you can get zero crossing switching which can smooth things out and you end up with less EMF (which is not really and issue for resistive heating loads).

For a HERMS/RIMS you probably want faster control, but for HLTs you don't.

SSRs have disadvantages, like cost and needing a heatsink.

#9 glaab

glaab

    Beer Dog

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 909 posts
  • Joined 12-May 09
  • Location:Grange, SA

Posted 10 February 2010 - 12:27 AM

As a radio tech I cringe at even the mention of anything that's not solid state.
I've replaced dozens of mechanical relays over the years but can only remember one or two dead SSR's.
They will cost about $5 more and outlast a mechanical device by a mile. Like Vince says, "I dunno, it sells itself!" They do lack that retro, pre Shockley electro-mechanical charm though. Maybe you're just hooked on that relief you feel every time your relay works. :icon_cheers:

#10 Lilo

Lilo

    Mini Mash

  • Members
  • PipPipPipPipPipPip
  • 198 posts
  • Joined 03-June 07
  • Location:Brisbane

Posted 10 February 2010 - 02:35 PM

As a radio tech I cringe at even the mention of anything that's not solid state.
I've replaced dozens of mechanical relays over the years but can only remember one or two dead SSR's.
They will cost about $5 more and outlast a mechanical device by a mile. Like Vince says, "I dunno, it sells itself!" They do lack that retro, pre Shockley electro-mechanical charm though. Maybe you're just hooked on that relief you feel every time your relay works. :icon_cheers:



Thanks Glaab... I am a Radio Tech myself, at least was when I was on the tools..
More trying to best utilise bits I have laying around. Shed full a crap I want to use up.

and your right, if nothing else the retro clunk is cool.


Cheers

PS Where do you practise your black art,,,