[Hack]

I am wanting to control my dust collector and router on / off via gcode through mach 3. I have been looking for relay boards with a large enough amperage rating to work, but have been unable to find any. The router being the larger of the 2 items draws 15 amps (110v porter cable 7518). Any suggestions as for a source or ready to use relay boards that will hanle this load?

CNC4PC has a solid state relay board that will handle 13 amps ($47.00) but I feel thats not big enough.

Thanks

Dan

[widgitmaster]

The nice thing about realys is that you can control a large amp relay with a low amp relay!

When I built my CNC Router, I used Bob Campbells LPT Breakout board with built in relays, that way the Gcode can turn the spindle, vacuume on/off as well as a vacuume pump for holding small parts!

http://www.campbelldesigns.com/breakout-board.php

This board is the nicest I've seen, and has more features than all the cheaper ones!

I hope this helps you!
Eric

[pminmo]

Here is a SSR for 25A at the bottom of the page. http://www.futurlec.com/RelSS.shtml
You can control it via a breakout board, one pin of the parallel port and a power supply..... they also have them bigger than 25A

[2muchstuff]

Conventional relays will arc across the points, pitting them when used with heavy inductive loads at high amperages. SSR's eliminate the arcing problem making them a better long term solution.

[arturod]

Dan,

The relay board you mentioned has the following features:

1. It includes 4 relays.
2. It is solid state, not based on cheap mechanical relays that cause arcs. These arcs limit the life of the relay and the motors you are using.
3. The board uses 40 and 12 amp triacs. I just rate the board to 1/3 of its maximum usage just in case some tries to use a motor that draws lots of amps during start-up.
4. Input signals are buffered and optoisolated.
5. It has replaceable fuses for better protection. In some cases users might want to replace the fuse with smaller ratings for specific needs or additional protection.

Please let me know if you have further questions.

Arturo Duncan
http://cnc4pc.com

[Hack]

Art,

So what I need to know is can I run the 15 amp router that I mention as well as a 6.5 amp dust collector from your board? Also, how do I wire it up? I noticed in the manual that it says "ttl signal from parallel" What is this. Does this come from the breakout board (I am using one of yours) or does it have to come directly from the parallel port cable?

How do you wire the devices? Is it as easy as just hooking up the positive and negitives of the power cord of the device to be controlled to the board?

Thanks

Dan

[arturod]

Dan,

Yes, you can run your 15 amp router and 6.5 amp dust collector with one board, and you would still have two more switches available. The board comes with 30 and 8 amp fuses. If they blow you can replace them high larger fusses, but do not exceed the 40 and 12 max amps of the triacs.

You need a 3 to 5 vdc input signal. It can come from your parallel port or any breakout board.

You wire this device as any other regular switch. Just pass one of the power cables through the screw connections, that is all. Imagine you where installing a switch for a light bulb, you would pass one of the cables through the screw on connections of the light bulb. You can use any of the cables. It does not matter if it is the live or neutral wire.

Arturo Duncan
http://cnc4pc.com

[HayTay]

Err...??? Arturo and Hack,

From the CNC4PC Solid State Relay Board SSRB4 website (it's also in the SSRB4 PDF manual )

• Controls 4 AC devices per card

• One switch for an up to 13amp motor.

• Three for up to 5 amp motors.

According to my math Hack's 15 amp router and 6.5 amp dust collector exceed the board ratings by 1.5 - 2.0 amps. On start-up, as far as I know, the motors will temporarily draw even more current than this. How can this be good?

I'd like to pick up a relay board, too. My router draws 11 amps and I haven't picked out a motor for the dust collector yet.

Help me out here,

HayTay

[arturod]

HayTay,

Keep in mind we are using 40 and 12 amp triacs on these relays. I am rating the relays to 1/3 of they max Triac rating. The thing is that it is hard to tell how each motor will behave on start-up. I have one of these relays rung a 20 amp motor, that is what make me confident to recommend it. In any way, the relay has replaceable fuses and there is no harm that can be caused to the hardware. In the worse case scenario, I refund upon return of the product if for any reason it does not work right.

Arturo Duncan