585,729 active members*
4,563 visitors online*
Register for free
Login
Results 1 to 3 of 3
  1. #1
    Join Date
    Mar 2007
    Posts
    29

    Solid State Relays

    On my homebrew CNC woodrouter I'd like to control the motor via a solid state relay via a spare port off controller board. I see a bunch of these relays on eBay but many list the specs which say they can't be used for inductive loads, although they will handle the current and AC voltage.

    I thought about just using a JFET switch off the port to turn on/off a heavy duty mechanical relay which will then control the motor - this would get me around any problems with inductive loads, but this is sorta a "messy" solution.

    Anyone have any advice with the SS Relays?

  2. #2
    Join Date
    Jun 2004
    Posts
    6618
    I bought a solid state relay to run my spindle motor. I didn't realize that there is more to it that just that. It was cheap though.
    I might eventually build a circuit that can use it. There were a couple of old threads here somewhere that explained and had a diagram about how to use SSR with cnc stuff.
    I just did a search and came up with those threads then.
    I decided to get the relay card from CNC4PC. They have several different types and one should suit your needs. Reasonable on cost as well.
    I still haven't had time to install these yet, but I will get there one day.
    Lee

  3. #3
    Join Date
    Dec 2003
    Posts
    24220
    The majority of AC loads are inductive and SSR's are used all the time for this, as long as the rating is OK and most are Zero switching, these switch the inductive load as the voltage wave form passes through zero.
    If relatively high loads like large contactors or solenoids etc, a snubber across the coil is recommended, if the current is slightly out of phase a snubber will help.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

Similar Threads

  1. Router 0/1 with solid state relay
    By bigz1 in forum CNC Machine Related Electronics
    Replies: 6
    Last Post: 04-25-2008, 02:37 AM
  2. Solid state welder schematics?
    By DennisCNC in forum CNC Machine Related Electronics
    Replies: 0
    Last Post: 07-09-2007, 10:55 PM
  3. Solid state relay
    By N4NV in forum CNC Machine Related Electronics
    Replies: 13
    Last Post: 05-07-2006, 06:19 AM
  4. Solid State Relays
    By vertcnc in forum CNC Machine Related Electronics
    Replies: 11
    Last Post: 12-01-2004, 01:45 AM
  5. Solid state limit switches
    By Swede in forum CNC Machine Related Electronics
    Replies: 0
    Last Post: 01-04-2004, 01:22 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •