Heatbed maxes out at 58 deg with SSR
Posted by alvinaw11
|
Heatbed maxes out at 58 deg with SSR October 31, 2015 12:39AM |
Registered: 9 years ago Posts: 11 |
Hello everyone,
I'm having difficulty getting my bed temp to exceed 58 degrees since I've hooked up my SSR.
It's a SSR60DD that I hooked up since this is a huge 6' tall printer that will be printing for 8 hours plus and wanted the precaution of not frying my electronics.
I've tried different gauge wire from 16 14 and 12 and it has effected temp eat up time, but the max out at 58 degrees. Is this because of my choice on the SSR? It seemed to work fine when I had it directly connected. I should note that the wires from the ramps board to SSR is still 18g, but I wouldn't think it would effect it.
I'm having difficulty getting my bed temp to exceed 58 degrees since I've hooked up my SSR.
It's a SSR60DD that I hooked up since this is a huge 6' tall printer that will be printing for 8 hours plus and wanted the precaution of not frying my electronics.
I've tried different gauge wire from 16 14 and 12 and it has effected temp eat up time, but the max out at 58 degrees. Is this because of my choice on the SSR? It seemed to work fine when I had it directly connected. I should note that the wires from the ramps board to SSR is still 18g, but I wouldn't think it would effect it.
|
Re: Heatbed maxes out at 58 deg with SSR October 31, 2015 04:03AM |
Registered: 8 years ago Posts: 5,232 |
|
Re: Heatbed maxes out at 58 deg with SSR October 31, 2015 05:04AM |
Registered: 10 years ago Posts: 14,672 |
Low cost DC-DC SSRs have between 1.5V and 2V drop. Heater power varies as the square of heater voltage. So the voltage drop explains the reduction in temperature. You will also find that the SSR generates a lot of heat.
My solution is to use an AC mains voltage heated bed driven by a DC-AC SSR. Follow the link in my signature for more.
The simplest way for you to get your existing bed heating properly is to buy a good DC-DC SSR with a low voltage drop. Crydom make good ones. Expect to pay a lot more than you did for your existing SSR.
Edited 1 time(s). Last edit at 10/31/2015 05:05AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
My solution is to use an AC mains voltage heated bed driven by a DC-AC SSR. Follow the link in my signature for more.
The simplest way for you to get your existing bed heating properly is to buy a good DC-DC SSR with a low voltage drop. Crydom make good ones. Expect to pay a lot more than you did for your existing SSR.
Edited 1 time(s). Last edit at 10/31/2015 05:05AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
|
Re: Heatbed maxes out at 58 deg with SSR October 31, 2015 08:03AM |
Registered: 8 years ago Posts: 916 |
|
Re: Heatbed maxes out at 58 deg with SSR October 31, 2015 09:06PM |
Registered: 9 years ago Posts: 11 |
Quote
dc42
Low cost DC-DC SSRs have between 1.5V and 2V drop. Heater power varies as the square of heater voltage. So the voltage drop explains the reduction in temperature. You will also find that the SSR generates a lot of heat.
My solution is to use an AC mains voltage heated bed driven by a DC-AC SSR. Follow the link in my signature for more.
The simplest way for you to get your existing bed heating properly is to buy a good DC-DC SSR with a low voltage drop. Crydom make good ones. Expect to pay a lot more than you did for your existing SSR.
How would I know which relay to choose out of their line up?
[www.crydom.com]
I'm very new to electronics and have only made my printers by mimicking other setups I've seen so I don't know how to read all the voltage stuff yet, I basically just copied my folgertech onto a much larger setup with better wiring and a IEC mains. Currently running 12v power supply and heatbed sorry I'm a complete noob to this I need to find a book to teach me the basics.
Also I did try a DCDA setup, but the heatbed would not shut off when I commanded it to through ramps
Edited 2 time(s). Last edit at 10/31/2015 09:10PM by alvinaw11.
|
Re: Heatbed maxes out at 58 deg with SSR November 01, 2015 03:31AM |
Registered: 10 years ago Posts: 14,672 |
I did a quick search on what is readily available, and the the least expensive one I found that I consider suitable was the DC100D40C.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
|
Re: Heatbed maxes out at 58 deg with SSR November 01, 2015 09:31AM |
Registered: 9 years ago Posts: 1,159 |
|
Re: Heatbed maxes out at 58 deg with SSR November 01, 2015 12:14PM |
Registered: 10 years ago Posts: 14,672 |
Quote
dougal1957
Quote
dc42
I did a quick search on what is readily available, and the the least expensive one I found that I consider suitable was the DC100D40C.
Youch £65 at RS makes my AC one seem very cheap at around £40 inc the SSR and at 400x400mm
Doug
Yes, good DC-DC SSRs are expensive. They have to feed power from the control side of the relay through to the load side in order to provide enough voltage for the gate of the output mosfet. Whereas DC-AC SSRs used to drive mains-voltage heated beds use triacs and the voltage drop is far less important because of the lower bed current. I paid less than £10 for my DC-AC SSR.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
|
Re: Heatbed maxes out at 58 deg with SSR November 01, 2015 08:38PM |
Registered: 9 years ago Posts: 11 |
|
Re: Heatbed maxes out at 58 deg with SSR November 01, 2015 11:00PM |
Registered: 10 years ago Posts: 14,672 |
I suggest you bypass your SSR and then test whether the bed gets hot enough. Also tell us what voltage and current the bed heater take. Without that information I can't estimate how much heating power you will lose with each type of SSR.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
|
Re: Heatbed maxes out at 58 deg with SSR November 01, 2015 11:43PM |
Registered: 8 years ago Posts: 916 |
Cripes, no need to drop that sort of dough.
Something like this would do the job: http://www.jaycar.com.au/Electromechanical-Components/Relays-%26-Accessories/Panel-Mount/Heavy-Duty-Chassis-Mount-Relays---30A/p/SY4040
Something like this would do the job: http://www.jaycar.com.au/Electromechanical-Components/Relays-%26-Accessories/Panel-Mount/Heavy-Duty-Chassis-Mount-Relays---30A/p/SY4040
|
Re: Heatbed maxes out at 58 deg with SSR November 02, 2015 04:20AM |
Registered: 9 years ago Posts: 445 |
Quote
nebbian
Cripes, no need to drop that sort of dough.
Something like this would do the job: http://www.jaycar.com.au/Electromechanical-Components/Relays-%26-Accessories/Panel-Mount/Heavy-Duty-Chassis-Mount-Relays---30A/p/SY4040
It's mechanical, so it would probably wear out rather quick + plus it would make the printer noisier.
|
Re: Heatbed maxes out at 58 deg with SSR November 02, 2015 10:12AM |
Registered: 9 years ago Posts: 1,159 |
Quote
Koenig
Quote
nebbian
Cripes, no need to drop that sort of dough.
Something like this would do the job: http://www.jaycar.com.au/Electromechanical-Components/Relays-%26-Accessories/Panel-Mount/Heavy-Duty-Chassis-Mount-Relays---30A/p/SY4040
It's mechanical, so it would probably wear out rather quick + plus it would make the printer noisier.
I Agree with Koenig something like a seven switch would be better
or Power Expander Whilst I have one of these it is as yet unused so can't comment on it's performance in use.
Doug
Edited 1 time(s). Last edit at 11/02/2015 10:20AM by dougal1957.
|
Re: Heatbed maxes out at 58 deg with SSR November 02, 2015 07:50PM |
Registered: 9 years ago Posts: 11 |
Quote
dougal1957
Quote
Koenig
Quote
nebbian
Cripes, no need to drop that sort of dough.
Something like this would do the job: http://www.jaycar.com.au/Electromechanical-Components/Relays-%26-Accessories/Panel-Mount/Heavy-Duty-Chassis-Mount-Relays---30A/p/SY4040
It's mechanical, so it would probably wear out rather quick + plus it would make the printer noisier.
I Agree with Koenig something like a seven switch would be better
or Power Expander Whilst I have one of these it is as yet unused so can't comment on it's performance in use.
Doug
THANK YOU that looks perfect
|
Re: Heatbed maxes out at 58 deg with SSR November 02, 2015 09:24PM |
Registered: 10 years ago Posts: 14,672 |
I can't find any specification of that Power Expander, so no way of telling whether it is suitable or not.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
|
Re: Heatbed maxes out at 58 deg with SSR November 03, 2015 02:22AM |
Registered: 9 years ago Posts: 445 |
Quote
dc42
I can't find any specification of that Power Expander, so no way of telling whether it is suitable or not.
Quote
TECHNICAL SPECIFICATIONS
Power handling designed for 12 to 24V DC (absolute maximum 30V DC)
Signal_in 5 to 24V DC
Signal_in and power_in are galvanically isolated.
Maximum power current up to 60A peak (unfused)
Board outline 30X30mm
Mounting holes 22X22mm (Ø3.2mm)
Please note that the Power Expander is unfused.
From the linked page.
Also: Datasheet for the driving MOSFET: PSMN7R0-30YLC
|
Re: Heatbed maxes out at 58 deg with SSR November 03, 2015 02:29PM |
Registered: 10 years ago Posts: 14,672 |
Thanks - maybe it's because I am using a smartphone, but I couldn't see the specification. It's a 6 terminal device rather than the usual 4 terminal SSR and that allows it to get the gate drive voltage from the output side. If it is correctly designed then it should be OK up to about 20A current, perhaps a little more, although nothing anywhere close to the 60A mentioned.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
|
Re: Heatbed maxes out at 58 deg with SSR November 04, 2015 02:50AM |
Registered: 8 years ago Posts: 5,232 |
Sorry, only registered users may post in this forum.