Heatsinked resistos?

Scribble · 26th March 2009, 12:37 PM

Hi Guys,

I have 4 0.5ohm/10w power resistors that come in a gold heatsink housing. They have 2 small tabs with mounting holes on the sides.

My question is, at what point will i have to mount these to another heatsink? i plan on using them in a CRC arrangement in an Aleph 30 PSU. Will they be ok on their own or should they definitely be mounted down?

Similar to this

Thanks for your time

wg_ski · 26th March 2009, 01:03 PM

You can only get full power rating when bolted to a heat sink. Usually, a chassis is fine for that purpose. Those metal cased resistors tend to be physically small for their size - ie, a 25W unit is about the same physical size as a 5 to 7 watt normal sand-box or dog-bone. With no heat sink in free air you'd have to de-rate somewhat.

infinia · 26th March 2009, 01:13 PM

For those type resistors start looking at mounting options and ambient temps at around 1/2 rated dissapation.

Scribble · 26th March 2009, 09:06 PM

Thank's guys, much appreciated.

woody · 26th March 2009, 09:30 PM

One other thing. If you realy overload one of these heatsink
resistors they can explode. I accidently overloaded a 50w device
while not on a heatsink to about 200w for a few seconds and
it blew up, sounded like a small firecracker.

26th March 2009, 12:37 PM	#1
Scribble diyAudio Member Join Date: Dec 2002 Location: Western Australia	Heatsinked resistos? Hi Guys, I have 4 0.5ohm/10w power resistors that come in a gold heatsink housing. They have 2 small tabs with mounting holes on the sides. My question is, at what point will i have to mount these to another heatsink? i plan on using them in a CRC arrangement in an Aleph 30 PSU. Will they be ok on their own or should they definitely be mounted down? Similar to this Thanks for your time

26th March 2009, 01:13 PM	#3
infinia diyAudio Member Join Date: May 2005 Location: Californication	For those type resistors start looking at mounting options and ambient temps at around 1/2 rated dissapation. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Modushop.biz heatsinked enclosure + F5 Amplifier (Nearly Complete) incl traffo	rhysh	Swap Meet	10	3rd July 2009 09:08 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

26th March 2009, 01:03 PM	#2
wg_ski diyAudio Member Join Date: Oct 2007	You can only get full power rating when bolted to a heat sink. Usually, a chassis is fine for that purpose. Those metal cased resistors tend to be physically small for their size - ie, a 25W unit is about the same physical size as a 5 to 7 watt normal sand-box or dog-bone. With no heat sink in free air you'd have to de-rate somewhat.

26th March 2009, 09:06 PM	#4
Scribble diyAudio Member Join Date: Dec 2002 Location: Western Australia	Thank's guys, much appreciated.

26th March 2009, 09:30 PM	#5
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	One other thing. If you realy overload one of these heatsink resistors they can explode. I accidently overloaded a 50w device while not on a heatsink to about 200w for a few seconds and it blew up, sounded like a small firecracker.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)