Hello Maxhawk,
I have two of your kits and they are great. Really well done. I am just wondering if it would be possible to add a few more relays on the same circuit? That way I could trigger on/off several units. I am just not sure if there is any limitation on the circuit that controls the relay.
Thank you
AR2
I have two of your kits and they are great. Really well done. I am just wondering if it would be possible to add a few more relays on the same circuit? That way I could trigger on/off several units. I am just not sure if there is any limitation on the circuit that controls the relay.
Thank you
AR2
AR2,
It depends on the coil resistance of the relay you choose to add. The transformer is good for about 200mA. So you'll need to do the math to see how much current is needed to turn on all the relays. An alternative would be to purchase 120VAC controlled relays and use the on-board relay to turn them on.
Also don't worry about the transistor that turns on the relay. Although the schematic says MMBT3904 for the transistors, I shipped everone MMBT4401 which has pretty much identical performance with more current capability. The 4401's are rated at 600mA while the 3904's I believe are 200mA.
Does this answer your question?
--Rob
It depends on the coil resistance of the relay you choose to add. The transformer is good for about 200mA. So you'll need to do the math to see how much current is needed to turn on all the relays. An alternative would be to purchase 120VAC controlled relays and use the on-board relay to turn them on.
Also don't worry about the transistor that turns on the relay. Although the schematic says MMBT3904 for the transistors, I shipped everone MMBT4401 which has pretty much identical performance with more current capability. The 4401's are rated at 600mA while the 3904's I believe are 200mA.
Does this answer your question?
--Rob
Well with some help from Max and Brian I have one of the soft switches working in a somewhat customized configuration.
http://www.briangt.com/gallery/coulomb-a5/DSC00251?full=1
If you visit this URL and look at the picture you will see th soft switch hiding under a small relay. I have cut the 5VDC and AC traces going to the on board Relay. I have shorted the two common contacts under the PCB. I have connected pin 2 of J3 to ground through a 1K resistor. In place of a jumper on J3 I have a pair of paralled thermistors that open at 75 Deg. C. they are normally closed.
When the main switch is powered on all the AC and DC supplies come on but the capaictors are not charged and two Aelph 5 boards not powered. This is my standby mode with just 2 low voltage DC fans quietly spinning away.
When I press the pushbutton the Softswitch trips the main DC relay which charges the caps and turns on the amps. If for some reason they reach 55 Deg. another pair of thermistors turns on the auxilary fan, if this does not work at 75 Deg. C the thermistor(s) across J3 will open and the softswitch defaults back to "off" position switching off the DC poser to the caps and amp boards. The main fan stays running until the temperature drops at which time the thermisors close J3 is reconnected and the switch goes active again turning on the DC. The relay is wired so that a 10R 50Watt resistor shunts across the caps when the relay is in the off position.
It all works very well.
Regards
Anthony
http://www.briangt.com/gallery/coulomb-a5/DSC00251?full=1
If you visit this URL and look at the picture you will see th soft switch hiding under a small relay. I have cut the 5VDC and AC traces going to the on board Relay. I have shorted the two common contacts under the PCB. I have connected pin 2 of J3 to ground through a 1K resistor. In place of a jumper on J3 I have a pair of paralled thermistors that open at 75 Deg. C. they are normally closed.
When the main switch is powered on all the AC and DC supplies come on but the capaictors are not charged and two Aelph 5 boards not powered. This is my standby mode with just 2 low voltage DC fans quietly spinning away.
When I press the pushbutton the Softswitch trips the main DC relay which charges the caps and turns on the amps. If for some reason they reach 55 Deg. another pair of thermistors turns on the auxilary fan, if this does not work at 75 Deg. C the thermistor(s) across J3 will open and the softswitch defaults back to "off" position switching off the DC poser to the caps and amp boards. The main fan stays running until the temperature drops at which time the thermisors close J3 is reconnected and the switch goes active again turning on the DC. The relay is wired so that a 10R 50Watt resistor shunts across the caps when the relay is in the off position.
It all works very well.
Regards
Anthony
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