I just upgraded my 8 year old compact router to a the 110v spindle/vfd.
The old compact router was plugged into a fein turbo 1 shop vac (turns on/off the vac when router turns on/off). Works great and is reasonably quiet. The router drew 6 amps and the vac draws 9 amps. plugged into a 20 amp circuit and all is good.
The specs on the vfd say it draws 12 amps. So plugging it into the Fein is probably not a good idea, correct? 12 + 9 =21 > 20 amp circuit and fein says don’t plug anything more than 6amp into the vac.
I was going to use an auto vac switch - but 12 amps for the vfd + 9 for the vac =21 > 20. May not be a good idea. Anyone running a vfd and a 9amp shop vac on the same electrical circuit? Any issues? Is the 12 amps a worst case start up at max speed? The auto vac switch has a delay for the shop vac to turn on so this may mitigate the issue.
The rated amperage are maximum. Usually only on startup does the maximum amperage is drawn and after initial startup the amperage drops.
The only way to tell what it runs when running is to measure the amperage on startup and running with a volt meter. You would be on the hairy edge but one way to find out would be to try. The worse that could happen is you pop a breaker.
Question: If I put the vac and spindle on one circuit and the computer/machine on another circuit, is the machine smart enough to stop a job if the spindle losses power due to a vac/spindle circuit trip? Or will the machine keep moving with the spindle off?
By itself the vacuum pulled 13.5 amps at start up and ran around 10.5 amps. Note the fein advertises 9 amps and a “soft” startup.
By itself the VFD set at 18000 rpm pulls 2 amps at start up then rans at 1 amp (with no cutting load).
Computer pulls .5 amps,
When running a job (no cutting load) the machine pulls about 1 amp
Running all four on one circuit with a 3 second delay for the vacuum: At start up the system pulls 15 amps (+/- 1) and 12.5 steady state no cutting and 13 under a cutting load (hardwood at 18000 rpm 201 ¼ inch bit).
I think I am going to put the vacuum, spindle/vfd and the machine on one circuit. The machine is only adding a 1 or 2 amps to the pull. The computer can go on a separate circuit (and it has battery backup anyway). The risk of tripping a breaker is fairly low and it will most likely happen at start up. If it does trip, at least this way the machine stops and won’t try to push a non spinning router bit through hardwood. I’m guessing that’s really bad to do.
I’ll see how it goes, If I end up tripping the breaker a couple of times, I will put the spindle/vfd and machine on one circuit and the vac on another.
Anything wrong with my logic? In case you can’t tell I’m not an EE, but I do have several degrees in Math.
Note: watt meter appears to update the display every ¼ to ½ second, I may not be seeing the true peak amps pulled.
Another option is to get a speed controller for the shopvac - the full suction power of the shopvac really isn’t needed. I modified one of my shopvacs with a speed control module I got off of Amazon but you can also get ready-to-use-plugin units that don’t require re-wiring a shopvac motor. I run my shopvac at less than half its full power pull(450-500W vs 1200W) & get adequate air flow & suction most of the time - the bigger chips have more of a tendacy to fly out instead of being sucked up but all the micrometer dust gets sucked up just fine. I have my whole setup(SPro, shopvac, router, lighting, Rpi) running off a single 20A circuit & through a power monitor(very handy to see how much power the router/spindle pulls as it can give indication that bearings are shot or a bit may be dull). My shopvac starts/stops with my router. For most carving operations where cutting load is minimal, my total power useage is around 675-800W - that is with a C3D router.
If your spindle stops mid-job, the CNC will keep trying to push it through the stock material. This either breaks off the bit in the spindle, or causes some nasty noises as the stepper motors stall. It would be very nice to have a spindle/controller interlink so that the controller knows if the spindle is spinning or not & be able to pause/stop itself, but that is another layer of complexity.
Also, breakers are not ‘instantaneous’ current-cutoff trips. They do allow more than the rated current flow to pass without tripping provided it is just a surge(3-8sec). If the current draw is above the rated amps for an extended period, then they trip(the greater the overage the faster they’ll blow). Motors, especially for things like furnace fans, table saws, shopvacs, air condition compressors, etc - have a huge(like 3 to 5 times the steady state run current) instantaneous current draw when they first start-up - the key factor being that it only lasts for a very short time. Breakers would be terribly annoying if they tripped every time a major appliance motor spun up.
Be very careful with speed controllers. The vac was designed for full rpm for cooling the motor. I used to use a speed controller on an older PC 690 single speed router and it burned up the motor.
I have had no issue with my speed-limited shopvac overheating & I’ve had it running for well over 100 hours. The motor cooling air stream is still there at lower speeds. I positioned my speed controller inside the cowling specifically in that air path to keep it cooled properly.
Shopvac motors aren’t dealing with the same kind of load as a router motor & reduced current flow equals less heat generated. The worst for a shopvac is a plugged suction hose which does not stall the impeller/motor or prevent the motor cooling air stream from flowing.
However, I do agree that one must be careful with speed controllers as they are not all the same & have different ratings & such. Appropriate testing & validation is a must.