Machsupport Forum
Mach Discussion => Mach4 General Discussion => Topic started by: gorf23 on June 10, 2019, 11:30:40 AM
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I have two SSR relays DC in out,, two screws for in and 2 for out...
can these be wired for forward and reverse to the spindle motor? if so anyone have a diagram.. I'm a little bit challenged on wiring.
and in my mind I would need 4 relays to reverse + an -
Thanks Gary
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Hi,
you need double pole double throw to reverse a DC motor.
Your SSR is single pole single throw, ie you'd require four of them.
Craig
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The inverters we use will not work with a solid state relay to turn on the forward and reverse.
They need a mechanical connection.
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Hi Gary,
While 4 SSRs could be arranged to reverse a DC motor a small misstep will result in lots of smoke. You would need to provide outputs that turns two of the SSRs on for forward and the other two for reverse. The motor must be off when the switch is operated, both for electrical and mechanical reasons.
The best option would have been a DC drive with built in reversing but apparently you already have a non-reversing DC drive.
Otherwise a double pole, double throw relay (DPDT) is my recommendation. This still leaves you with the responsibility of making sure the motor is stopped when the relay is operated.
If it is not required to have the CNC controller reverse the motor a manual DPDT switch will do. If you want help selecting a suitable switch or relay let us know what part of the world you are in or which suppliers you prefer. Information about your controller would be needed to select the right relay coil voltage.
https://rollertrol.com/images/schematics/switches/DC-motor-reversing-switch-schematic-wiring-diagram-285x275.jpg
The link below is an example of a Drum switch for 3 phase power in an enclosure. Anything you do needs to be enclosed and mounted so a cheaper switch could cost more in the long run. Use the two sections of the switch that cross when the switch is reversed.
John
https://www.ebay.com/itm/Drum-Switch-Forward-Off-Reverse-Motor-Control-Rain-Proof-Reversing-60A/162858118863?_trkparms=ispr%3D1&hash=item25eb19aecf:g:GfIAAOSwsZJaYFmX&enc=AQADAAAB4KX%2FKt4E1xf3SDqEdBclaYZ10vu%2BpDAG5CNJxeT9K2jqgB5ozPPGVc9QXjiOOkPV2%2Bb1IYKwX8L7%2FswbEIjqQZp%2B9TLM6qrwO9fZV5sXV7xoo2jQSsTgDy0jMKSCGPWCuCl85e5rmc4kUqIOj1S%2F1v7dtLxSJD2BI5sXEFx32FJJYn9ywNTqrUY%2BAw%2BhaIbmupi4y7ua9smU00%2F5JgTsaGnM7A0iPZkZWnMGd9h5IpxgNvOz%2B%2FdbYqrxaEdPPTEnm1b8rUogp66S6U8r7jA6uApxZCLawDgpcpYOstqn5nlusbJaK797Dn6QULK7wE45hzxtiu6qHmmOtGNUGoY31W77ekSmGwl7d%2FzKBRJp0GKUi7RF7dPtrPt8PYxVob23Zx7YKYkCk4vrFPoHAHT7WTg1yoEVrB6dCUHGMww6BZnFh0XYavO5kX%2FKhRRcmTgss2uMYGkfObNoCOErvqYd%2BLzn6N8MBRBlblkeu%2Fcv%2BxjL1ew1mZiRZIHLjrY156imXKFWio3XSD2BiMR%2F%2F0Z6znZ3ALMkGgXmYfqgGT8UAei0meQA5AKq8fKrFiyGVOBxLJU4jdwQqdkiCjnWq8zFaTJAyF9ssYmuh374N%2B7JvllJeUtPagGKiZ0n%2FYo4Clfppw%3D%3D&checksum=162858118863a735ed1c7d04478fb1145156fef0b7e1
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Ok thanks, my motor controller is a KBWS-25D connected manual and also with the computer control have it working with mach 3 4 and also Auggie both with ESS smoothstepper and pokeys57cnc..
I did think i would need a DPDT relay, I also think i would need two 0f them ?
Have the thing apart right now so just though i would try to get motor to reverse, but maybe to much trouble,
with Auggie i write my own code to control m3 and m4 so turning off the spindle before switching any relays would be fairly easy, but only works with the pokeys, not sure about mach4 yet.. is m3 m4 hard coded in mach4 ?.
Thanks gary
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One DPDT relay will do the job.
John
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Thanks the problem i'm having right now is finding a dpdt relay for dc to dc thats at least 0-130dc output 3-32 input...
thanks gary
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Your mention of 3-32 volts make me wonder if you are thinking about a SSR.
I am suggesting a mechanical relay. If I knew what part of the world you are in, or your preferred suppliers, I could find an appropriate relay.
Assuming you will use 12VDC here is one possibility.
Relay
https://www.automationdirect.com/adc/shopping/catalog/relays_-z-_timers/electro-mechanical_relays/square_-z-_cube_relays,_plug-in,_3a_-_15a_(78x-z-_qxx-z-h78x_series)/general_purpose,_15a_(781_-z-_782_-z-_783_-z-_784_series)/782-2c-12d
Socket
https://www.automationdirect.com/adc/shopping/catalog/relays_-z-_timers/relay_sockets_-a-_accessories/relay_sockets/782-2c-skt
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Yes i was Thinking SSR, i'm im USA Florida
I am using +5 from the BOB to the relay i have it now just to turn on the spindle power and flood... it rated enough for the 120v out but dc out is only rated to i think around 30v so that won't work for reverse forward, and its a spst.
thanks gary
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Having only a 5V signal from the breakout board limits my choices. Also I am trying to keep this circuit easy to build.
My solution is to use a SSR as a buffer between the BOB and the relay. Since there is no DC power available for the relay I have selected an AC relay.
The voltage and current rating of a relay is the the combination it can safely interrupt. As you will be turning the drive off before switching the 30 VDC rating of this relay does not apply to your application. Still at $2.50 each you could by a few spares in case an accident causes the relay to operate when power is on.
This supplier is located in Riviera Beach, FL.
Relay
https://www.mpja.com/Relay-DPDT-5A-110VAC-Coil/productinfo/33972+RL/
Socket
https://www.mpja.com/DIN-Relay-Socket-for-DPDT-HH5-Relays/productinfo/33974+RL/
SSR
https://www.mpja.com/10A-480VAC-Solid-State-Relay/productinfo/31931+RL
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Thanks that looks easy enough..
I have been rummaging around in so box's and found 4 SSR relays 2 are 3-32v and dc output 5-220vdc
and 2 are 3-32v and Ac output 24-380v...
any way to use these?..
Thanks gary
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The 3-32VDV in, 24-380VAC out SSR can replace the SSR relay on my list.
You should allow the motor to stop before changing direction with the relay. A spinning DC motor generates voltage.
The operating time of the relay is probably about 10 milliseconds. To be safe allow 20 mSec between changing it and enabling the drive.
There is a note in the KB drive manual warning that a shorted output transistor will cause the motor to run at full voltage. Your E-Stop should kill ac power to the drive.
It's a good idea to kill the power to anything hazardous (or expensive) with the E-Stop.
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One thing this stup turns on the reverse relay... for the dc motors
one thing I was doing is using a relay to turn on the 120v to the kb controller with m3
from the looks of the diagram I would need another relay to power the controller, sould I use one for each m3 and m4 ?. m4 would also have to switch on the reverse relays...
Gary
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If you need more relays we should do things a bit differently. There are many relay boards advertised as Arduino or Raspberry Pi compatible that will add relays to your setup. Below is a link to 4 relay board from the same supplier I mentioned before. You can usually get the same or similar products from China via eBay for less money but the delay is much longer.
This board may take more 5 volt power than your system can spare. A separate 5 volts supply would be the safe way to go if you can't verify the current supply can handle the extra load.
A spare 5V USB charger will do as only about 250mA is required. You may have one lying around unused.
Hookup is fairly easy but you would need to be able to use a voltmeter to make sure to get the polarity correct. If you think you have the skill to do this I can make a wiring diagram.
One of the 4 relays could replace the SSR relay for reversing, the others can be used to enable the drive and other things you may think of later.
https://www.mpja.com/Quad-Channel-SPDT-Relay-Board-Isolated-5V/productinfo/35685+MP
https://www.mpja.com/5-Volt-DC-Plug-Power-Supply-4A-Regulated/productinfo/18520+PS/
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I was using one of the eight board relays for Arduino worked ok with ESS smoothstepper..
But not so good with the pokeys57cnc the relay board must trigger with low voltage applied, when I hooked it up to pokeys it triggers the relay instance and can't shut it down..
I tested a couple pins on the pokeys and there was 1.6v all the time, when I triggered the pin it did go up to just under 5v.
but so for some reason 1.6v was enough to trigger the relays..
if I use the relays on the pokeys I can run 5v when closed thought them and that works...
it also has two SSR outputs but even with them there's a 1.6v output not triggered so they triggered the Arduino relays when turned on..
Gary
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Exactly which pins had 1.6 V and was anything connected to them when you made that measurement?
Can you supply information about the relay board, model number etc, that could led me to its wiring diagram?
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The relay board is a hivitronix 8 relays..
I was pulling the pins from the LCD connector on the pokeys pin 28 forget now if the other wire was to gnd or +5 when testing and yes I had it wired to the relays that's how I knew it was being turned on as soon as I applied power to the pokeys and had 1.6volts, like I said it did go to +5 volts when I triggered the pin 28..
and received the same results from the SSR output's on the pokeys.
Gary
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The voltage readings don't make sense. If you used SSR1 or SSR2 the worst you should have had was 0 volts one way and a voltage between 0 and 5V the other way. I suspect something was miswired.
How did you connect the ground of the Pokeys to the relay board, which terminals?
What did you use to supply the 5V power to the relay board?
The relays on that board draw about 80mA each. If you get it working you'll need 8 X 80 = 640mA to run all relays.
I could not find much on your relay board, is it the one pictured in this link?
If so, what are the numbers on the IC near the input terminals?
https://www.ebay.com/itm/273842180913
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Yes your right,
I took a break, now I am getting the correct voltage from the SSR and the on board relays.
The Arduino relay's are working correct with both SSR onboard and on board relays... so I have 4 outputs working...
Yes that's picture is close to the board I have, mine has 2 screw terms 1 for vcc input voltage also a barrel connector for input voltage
and a 2 screw term I assume for output voltage...
I thing I can't seem to do is get any of the pins I try to use on the pokeys to work other than the relays, I tried the LCD connector and a couple others but when I set the pins I get no change to voltage.
I did get the LCD to change, but the problem was when I connected it to the relay SSR or Arduino it would read unconnected 4v connected 0
almost like it couldn't hold voltage when the relay was connected..
Gary
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The Arduino relay's are working correct
By Arduino relays do you mean the relay board?
I did get the LCD to change, but the problem was when I connected it to the relay SSR or Arduino it would read unconnected 4v connected 0
almost like it couldn't hold voltage when the relay was connected..
I don't understand what you were connecting to the LDC output. Was either an input on the relay board or the solid state relay module?
If you can make an LCD output switch from 0 to 5V it should be able to drive the relay board input.
If you connect 5V power to the relay board do the inputs measure 5V?
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Yes
And they are only rated at 28v dc output..
Gary
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I'll assume yes means the inputs measured 5V.
What is rated at 28VDC?
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sorry for miscomputation..
No its +5 in and 120 220 volt out, and the max dc output is 28v .
That's what is printed on the relay..
Gary
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I don't know why the LCD output doesn't work for you, it should.
Your success with operating the relay board from the SSRs and the PoKeys relays tell me the 4 OCx outputs could be used with the relay board. I have attached a wiring diagram.
one thing I was doing is using a relay to turn on the 120v to the kb controller with m3
You shouldn't turn the 120 VAC on and off with M3 and M4. The analog voltage from the PoKeys starts and stops the drive. You do want a manual switch to turn off the drive during tool change. Don't trust the computer with your fingers.
One of the relay board relays or a PoKeys relay can be used to switch the AC to the coil of the high power DPDT motor reversing relay. Unless you have a DC power supply with extra current I would stick with the AC relay for the reversing.
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Thanks I was also looking at the relay board that pokeys sells but I think its output is rated at 28v dc also
I put a volt meter on the oc output's and wasn't getting enough output volts to power the relays, I will test it again..
I though they may be pwm like the spindle output, but most likely i'm wrong.. but there on the same isolated output connectors as the spindle.
there is a toggle switch plus a push and locked when closed, on and off power switches to spindle.
Gary
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The opto-isolated OC outputs do not supply voltage. Much like a relay contact, their two pins are together when switched on. Wiring them as shown in the diagram will connect the input of the relay board to ground, changing it from 5V to 0V.
The OC outputs are for motor controllers that have inputs for direction and enable etc. Your basic controller doesn't have them.
DC Current through a relay contact is harder to interrupt than AC current, hence the lower voltage rating.
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Thanks
The OC'S work great so I now have at least 8 outputs I can control the relays with..
Thanks gary
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Does this look doable ?
SSR Relays
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Hi,
because you have four independent SSRs you have in effect a DPTT (double pole triple throw relay) where with all four
SSRs off results in the motor being off.
Is it strictly necessary to have a fifth SSR in the AC input circuit?
Craig
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Do you keep a fire extinguisher close by?
The current rating is a marginal and if you ever fire both sets of relays at the same time lots of smoke will be let out.
Commercial solid state devices to do the job this way are uncommon and expensive. It's far safer to use a mechanical relay.
As I said before, not knowing how much DC power you have to spare, use a relay to switch AC power to the coil of a DPDT relay.
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Hi,
and if you ever fire both sets of relays at the same time lots of smoke will be let out.
That is correct, if you do not correctly program and time the activation of the SSRs you risk having all four on at one time
and disaster will strike.
If however you have an input relay and a DPDT relay on the output (for motor reversal only) then you need to sequence
the input relay BEFORE switching the reversal relay or risk blowing the contacts off the reversal relay, ie you have
to correctly program and time the activations of the relays.
Correct programming is required in both cases.......either solution works and either fail if you don't time activation correctly.
Craig
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The current rating of those SSRs is only 1 amp. Max surge current is 5 Amps. If one fails it can take out the others.
This is why I suggest using a cheap and easily replaced DPDT relay.
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Thanks could go either way still testing..
I assume a G4 would work in the g code?..
Gary
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The best way to providing reversing is to use a drive with that feature. Sometimes going the cheap route costs you more in the long run.
Also, There should be a fuse to limit the damage if when a fault occurs.
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Hi,
I assume a G4 would work in the g code?..
Yes, g4 in Gcode would cause a delay whereon you can change direction......but if you omit the g4 from your
code you blow up your relays and/or your drive. You should have a script in Mach4 that runs every m3/m4/m5
operation so that an inadvertent missing g4 doesn't wreck things.
That would apply to either SSR OR relay solution.
Craig
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The responsibility of providing the right timing could be shifted to the operator by having the code put up a message asking the operator to set a manual switch.
How often will a G code program ask for a spindle reverse mid-operation?
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How often will a G code program ask for a spindle reverse mid-operation?
That is a very interesting question.
I think we all know that if something is allowed to happen then sooner or later it will happen. ;)
Tweakie.
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So doesn't seem to work correctly, I wired it up per the diagram for the SSR relays
if I don't have the motor connected to both forward and reverse relays it works fine connect one set of relays and runs forward. remove forward relay wires connect the other two relays and it runs reverse.. great, but if I connect the motor to all 4 relays and turn on reverse the motor moves really slow and the plus wire from the relays turned on and the neg wire from the relays turned off over heat and smoke..
I don't see any thing wrong with the wiring so confused here..
Could I have a bad SSR relay, how to test it ?.. I did check the ohms on the outputs of all the relays 3 showed 0 ohms but one showed 278.89 ohms when relays where not power on so should be Open circuit ..
Did all testing off the mill on and old 12v motor,,
Thanks gary
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Expanding on my previous question, other than tapping I don't see a case where the G code would need to control the reversing of the spindle.
What do you plan to do that would require it?
The motor is stopped when a tool is changed so a manual switch could be used.
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Hi,
Could I have a bad SSR relay, how to test it ?.. I did check the ohms on the outputs of all the relays 3 showed 0 ohms but one showed 278.89 ohms when relays where not power on so should be Open circuit ..
Can you post an exact model code of the SSRs you are using? I noted that in the diagram you posted you showed the
internal representation of the SSR as a MOSFET with an anti-parallel freewheeling diode. If that is indeed the internal
structure of the SSR then you can under no circumstance reverse bias it because the freewheel diode 'shorts' the
applied reverse voltage.
As MN300 has pointed out a mechanical DPDT relay even with the addition of a SPST relay to isolate or turn off the spindle
is an easier proposition if you are not familiar with electronics. Unlike MN300 I think a suitable DPDT relay is not going to be cheap.
I have had many occasion to reverse DC motors as a result of working with welding equipment for some years.
We stocked open frame relays such as this for the purpose. They are not cheap but they are good and therefore did not come
back as a warranty claim on our work.
https://nz.element14.com/potter-brumfield-te-connectivity/prd-11dh0-24/relay-dpdt-125vdc-20a/dp/1386559 (https://nz.element14.com/potter-brumfield-te-connectivity/prd-11dh0-24/relay-dpdt-125vdc-20a/dp/1386559)
Note the price in this link is in NZD.
Craig
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Yes, a relay that can actually interrupt the full motor current isn't cheap. A $43 relay and 24 volt power supply to operate it is bringing the total cost nearer the price of a proper reversing drive.
https://www.newark.com/search?st=PRD-11DH0-24
https://www.minarikdrives.com/mdpm03-d230-4q-pcm
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Hi,
there is an arrangement where you can use MOSFET/anti-parallel diode SSRs.
I have left out the connections to the opto diodes, they are switched as pairs, K1 and K4 together OR K2 and K3 together.
Craig
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Hi MN300,
the relay to which you linked to from the Newark site is the indentical one to which I linked to on the Element14 NZ site.
Newark and Element14 and Premier Farnell are ALL the same company.
Craig
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Yes, that's a USA link for gorf23 who lives in Florida.
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Hi,
we actually stocked Allen Bradley relays of the same type, there must be an effective industry standard which different
manufacturers use to provide competing products.
They are still 'American Made' when that used to mean top quality. I have replaced these relays after 30 years service
reversing wire drive motors in sub-arc welders (150VDC motors)....they are truly rugged and reliable. Not to say you
couldn't wreck them by trying to switch direction with the motor at full speed without allowing a de-acceleration pause.
Craig
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I did get the SSR relays to work Forward and reverse...
Tested on an old motor haven't tried on the mill yet, its been to hot here in Florida to mess around in the garage been getting up to 105%
no air in garage, have to wait for a cooler day..
Thanks for all your help..
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Craig
I did get a couple of the relays you suggested the 2 120v dtdp relays..
I hooked them up only to power 120v and powered them up I get a hum noise that I think is normal,
but when powered on, no click they are not going for NC to NO the red led lights in the relay but the blue doesn't, I also don't see the contacts switching, they should switch as soon as powered up Right?
Any suggestion broth are doing the same thing...
Gary
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Hi,
post a picture please. Those relays came equipped with a variety of different coils.
Sounds to me lie you are using AC on a DC coil or vice versa. A close up of the spec is required.
Craig
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I'm not sure what it was but got it working tested the AC volts at the relays and was only get 60, voltage was cut in half rewired it and it good now..
But of course ran into another issue, when I toggle these two relays for manual spindle control.. and I still have the pokeys board relays still plugged into the spindle relays and then turn on the manual relays with the pokeys powered off it seems to back feed voltage to the pokeys though the pokeys relays and power up the pokeys …
something else to work on don't want to blow the pokeys...
Haven't tried it yet with the ESS don't think I will take the chance will have to figure a way not feed power back to the controllers if the relays are still plugged into the boards..
Thanks gary
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Hi,
what on earth are you doing? The whole point of using relays is galvanic isolation between the input (coil)
and the output contacts.
If the output is somehow back feeding, even powering up the PoKeys THEN STOP IMMEDIATELY.
Disconnect everything, you have gone wrong somewhere. What circuit diagram are you following?
If you are not 100% on electrics then you cannot 'wing it' or do it 'by eye'.
Still need the specification of the relays, the coil voltage particularly.
How have you got Mach setup?
1) One relay for ON/OFF and another relay for FWD/REV....OR
2) One relay for FWD, one relay for REV. If neither is operating then the spindle is OFF
Either MN300 or I will help with a circuit diagram.
Craig