I haven't designed a circuit in more years then I care to mention so I know I need help. What I want to do is .. control a table saw and a shop vac. When I turn the circuit ON...table saw and shop/vac on immediately When I turn the circuit OFF... table saw off immediately and shop/vac to run for approx. 5 seconds longer and then turn off. If your able and/or willing to help I'll give you the specs for both pieces of equipment.
Help with Circuit Design
Jan 20, 2007
12 Replies
At it's crudest level...
2 relays, a diode, resistor and a capacitor..D from BC
Just go here:
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and search for H3DE timer. It does exactly what you want.
John B
Your table saw switch already does exactly what you want it to do for the table saw. For the shop vac, all you need to do is connect a timer relay as mentioned in the other posts to the "output" of your table saw switch.
Chuck
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You only need one relay - for the vac. Also, you will need a rectifier and transistor to drive the relay.
Tam
Why not just use a normal relay (or just a switch) for the table saw
and an off-delay relay for the shop-vac?
View in Courier:
OFF-DELAY
+----------+ +-----+
LINE>---O----------|COM NO|---| VAC |----+
| | | +-----+ |
| ----------------------------------------+
Basic Stamp.
Many thanks,
Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com
Please visit my GURU\'s LAIR web site at http://www.tinaja.com
Sears sells a plug in box that does just that. Of course you could roll your own. I would start by detecting the current in the table saw circuit, then have a relay close energizing a second feed to the shop vac. I know my shop vac is something like 13A, and my saw is probably close to 15A therefore I suggest using two separate feeds.
Search for a delay off timer.
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On Sat, 20 Jan 2007 10:28:32 -0700 in sci.electronics.design, Don Lancaster wrote,
Hah! A 555 would be cheaper.
Go to this link
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and look for "Power Off Time Delay Relay Circuit" near the bottom
I second that but use 1 solid state relay, 1 diode , 2 resistors (voltage divider) and 1 capacitor..... bobs your uncle.
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Thanks for the suggesti>
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