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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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12vdc solid state timer-relay
Are the commonly available octal base industrial timer relays (NCC, Dayton, ect.) compatible with a 12vdc load? Can find listings with 12vdc coil (input or control circuit) but all the outputs are rated for some motor HP rating, which I take to mean AC voltage. My load is a 12vdc solenoid (10A draw) that activates a pneumatic cyl., the release of which I need to time delay (delay on break).
If not, does anyone know of a combo timer-relay (min.adj. .01s, max adj. 5s) that will work in this app.? Have done a forum search, but did not find an answer. Many thanks in advance for any suggestions or advice. Keith LeBlanc |
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12vdc solid state timer-relay
On Jul 10, 5:44*am, voodooracer
wrote: Are the commonly available octal base industrial timer relays (NCC, Dayton, ect.) compatible with a 12vdc load? Can find listings with 12vdc coil (input or control circuit) but all the outputs are rated for some motor HP rating, which I take to mean AC voltage. My load is a 12vdc solenoid (10A draw) that activates a pneumatic cyl., the release of which I need to time delay (delay on break). If not, does anyone know of a combo timer-relay (min.adj. .01s, max adj. 5s) that will work in this app.? Have done a forum search, but did not find an answer. Many thanks in advance for any suggestions or advice. Keith LeBlanc -- voodooracer HP is commonly about 745 Watts, watts = volts x amps, so you can figure it out if you can multiply and divide. |
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#4
Posted to sci.electronics.repair
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12vdc solid state timer-relay
voodooracer wrote:
Are the commonly available octal base industrial timer relays (NCC, Dayton, ect.) compatible with a 12vdc load? Can find listings with 12vdc coil (input or control circuit) but all the outputs are rated for some motor HP rating, which I take to mean AC voltage. My load is a 12vdc solenoid (10A draw) that activates a pneumatic cyl., the release of which I need to time delay (delay on break). If not, does anyone know of a combo timer-relay (min.adj. .01s, max adj. 5s) that will work in this app.? Have done a forum search, but did not find an answer. Many thanks in advance for any suggestions or advice. Keith LeBlanc Easiest is to put a cap across the relay, adjust the value of the cap to hold the relay for the extra time you need. If you want precision, then use a 555 timer kit to drive the relay. Or you can do some research, and scrabble up a 555 delay circuit yourself. John :-#)# -- (Please post followups or tech enquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
#5
Posted to sci.electronics.repair
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12vdc solid state timer-relay
On 7/10/2012 10:49 AM, John Robertson wrote:
voodooracer wrote: Are the commonly available octal base industrial timer relays (NCC, Dayton, ect.) compatible with a 12vdc load? Can find listings with 12vdc coil (input or control circuit) but all the outputs are rated for some motor HP rating, which I take to mean AC voltage. My load is a 12vdc solenoid (10A draw) that activates a pneumatic cyl., the release of which I need to time delay (delay on break). If not, does anyone know of a combo timer-relay (min.adj. .01s, max adj. 5s) that will work in this app.? Have done a forum search, but did not find an answer. Many thanks in advance for any suggestions or advice. Keith LeBlanc Easiest is to put a cap across the relay, adjust the value of the cap to hold the relay for the extra time you need. If you want precision, then use a 555 timer kit to drive the relay. Or you can do some research, and scrabble up a 555 delay circuit yourself. John :-#)# You have at least two problems. Whatever you use to drive the relay needs to withstand the inductive kick when you turn it off. To fix that, you add a diode or some kind of snubber. But what does that do? It causes the current to continue flowing in the relay until the energy is dissipated in the coil resistance and/or snubber. That keeps the relay closed for some period of time. Same thing happens on the contact side. You need some kind of snubber to keep the inductive kick of the solenoid from arcing the relay contacts. Causes more delay for the same reason as above. You can get a rough estimate of the amount of extra delay from Td = L/R where L and R are the inductance and DC resistance of each of the coils involved. Bottom line: 10ms is kinda short for a reliable time delay for a mechanical relay. |
#6
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12vdc solid state timer-relay
You could use the timing relay to drive a conventional DC rated relay
which in turn would activate the solenoid. And see the section on "Protection diodes for relays" at http://www.kpsec.freeuk.com/components/diode.htm On 7/10/2012 4:44 AM, voodooracer wrote: Are the commonly available octal base industrial timer relays (NCC, Dayton, ect.) compatible with a 12vdc load? Can find listings with 12vdc coil (input or control circuit) but all the outputs are rated for some motor HP rating, which I take to mean AC voltage. My load is a 12vdc solenoid (10A draw) that activates a pneumatic cyl., the release of which I need to time delay (delay on break). If not, does anyone know of a combo timer-relay (min.adj. .01s, max adj. 5s) that will work in this app.? Have done a forum search, but did not find an answer. Many thanks in advance for any suggestions or advice. Keith LeBlanc |
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Thanks again to all. Keith LeBlanc |
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