Thread: Router Speed controller

Originally Posted by Chris Parks

This may be of interest to some here, there are two versions 120V & 240V mains supply. I wonder if it will control a CNC spindle? www.SuperPID.com - Super-PID Closed-loop Router Speed Controller

Looks like a nicely made device and it should control a single phase CNC spindle as long as it is a "Universal" type motor.

From what I can see the pros are
1) works on Single phase Universal motor systems
2) display with useful info
3) suited for single phase universal machines with integrated motor that cannot be replaced with a 3Phase motor

Cons.
1) Will not work on Single phase "induction" motor.
2) Existing machine speed control needs to be disconnected - could be electrically challenging for a DIY'er
3) US$155 plus enclosure plus 5V power supply puts it into the VFD + used 3Phase motor price range.

Of course a VFD does a lot more than speed control so there are benefits.
Degree of difficult and danger looks about the same as adding a VFD - where that is possible of course.

They're promoting it as something that makes the motor quieter but don't see how it can make that much of difference when the power tool is at full power?

Originally Posted by BobL

They're promoting it as something that makes the motor quieter but don't see how it can make that much of difference when the power tool is at full power?

Typical marketing spin - quieter when you turn the speed down.

This is probably a bit late but.....Silicon Chip magazine and Jaycar Electronics used to produce a universal motor speed controller for 240V "universal" motors, the ones with brushes rather than the induction type motors. The last one I built was pretty basic and not real expensive. I used it to control an old fixed speed drill that I was using to drive a wood lathe. I rekon with a bit of fiddling it could be made to work with a machine that had a blown speed controller that was no longer available.

It looks like a nice bit of gear Chris. If it is actually PID control (and I have no reason to believe it isn't) it would perform much better than the DIY speed controllers. The beauty of a PID loop is that it can be tuned and optimised for your application. Although this can't be tuned they claim it has been optimised for router operation. It is pricey but there aren't many (good) options for single phase.
Edit: just noticed the original posting date. Missed this when it was first posted.

Just re-reading the blurb in the ad....I wonder how effective the infra-red optical sensor would be in the dust-laden atmosphere surrounding the average router collet? If the motor has a power output of "X" watts running at full power and with no speed control mechanism modifying the electric supply, how does this machine make it more powerful? Somewhere along the way there is something that just doesn't seem quite right in there somewhere. The optical feedback to control the motor speed is fine but getting more power out of the motor at lower speed seems optimistic. Then there is the problem of heat dissipation in the motor. Increasing the power to the motor means more heat which would be fine if the motor was spinning faster (airflow generated by the internal cooling fan increases with motor speed) but the ad implies we can get full power at low speeds. What about the cooling air flow?

Hi, this is similar to the way most good speed controls work on a router using a HALL effect sensor / optical sensor etc. When the router is running at a lower speed the controller increases or decreases the power to the motor as the load changes to maintain the set speed - up to the set design power limits of the motor (one would hope). As you rightly pointed out, heat will be a problem as motor fan speed is lower at reduced speeds if pushed to near full power.

It would come down to how long the motor is running, how hard you are pushing it (loading it up), the amount of external air flow around the motor "that can actually cool the motor windings" and working speed.

The optical sensor should be fine with reasonable dust extraction and a strong optical light source over a short distance with a big stripe of white reflective paint.

At the end of the day I personally would not purchase another plunge router for my table, instead I'd go with a CNC router motor and a VFD, motor ratings between a CNC and a typical Router are different, a CNC of the same power is in reality a more powerful beast and it's usually a continuous use rating.

Originally Posted by NCArcher

It looks like a nice bit of gear Chris. If it is actually PID control (and I have no reason to believe it isn't) it would perform much better than the DIY speed controllers. The beauty of a PID loop is that it can be tuned and optimised for your application. Although this can't be tuned they claim it has been optimised for router operation. It is pricey but there aren't many (good) options for single phase.
Edit: just noticed the original posting date. Missed this when it was first posted.

Tony, contributing knowledge is always good no matter when it happens and thanks for that info.

Originally Posted by MandJ

At the end of the day I personally would not purchase another plunge router for my table, instead I'd go with a CNC router motor and a VFD, motor ratings between a CNC and a typical Router are different, a CNC of the same power is in reality a more powerful beast and it's usually a continuous use rating.

I think that is something we have agreed on in the past but most of us have the equipment already and to change would be nice but in the end the result would be the same machined piece of timber. If I was to start again no way would I use a router, plunge or fixed. I have the router motor and Kreg lift sitting in boxes brand new and unused and I have been close to selling them a few times and getting a water cooled spindle and VFD. It presents so many advantages for less money and for me the table mounted router has no fascination at all, in fact the spindle presents so many advantages that is a no brainer as the Americans would say. The big plus is the router lift is totally unnecessary with a spindle and that saves a huge amount of money.

Surely some type of lift would be necessary to change the bit height and for fine adjustments you would need a fine adjustment mechanism of one sort or another.

Also, can you use a VFD to control a 240V spindle?

i’m interested as this is the path I will probably follow if and when the Triton fails.

Short answer ..No. But you can do anything if you throw enough money at it.
You can get single phase VFDs but they only work on certain types of motors (not common types) and I suspect that they would be expensive. Not worth the effort unless you absolutely cannot use a 3 ph motor for some reason.

Thanks Tony. I thought so, but was left wondering after reading Chris’s post, as I thought a 415v CNC water cooled spindle would be over the top.

Originally Posted by Lappa

Surely some type of lift would be necessary to change the bit height and for fine adjustments you would need a fine adjustment mechanism of one sort or another.

Also, can you use a VFD to control a 240V spindle?

i’m interested as this is the path I will probably follow if and when the Triton fails.

Firstly the spindle is three phase so a VFD takes care of that. The lift only needs to move through a short range, maybe 50mm and with a spindle it can be side mounted onto a panel like this and controlled by a cam, threaded rod or both for that sort of range. See the linked videos, these are commercial examples but I am all for using ideas that have been proven already. The spindle comes with a side mount already made it just needs bolting to a panel/lift and multiple set spindle set ups are possible as shown in the videos. You then have no structural issues with the top as it does not have to support kilos of dead weight and I am sure the vibration does it no good either. It can be hinged or even lifted off which is a huge advantage. I have put up all these links and more in previous posts and if you want to see more have a search through this sub forum. Ruwi have heaps of videos out there and all of them are fascinating to some degree. I haven't seen this one before but at about two minutes it shows fine adjust the height of the spindle and under that is the coarse adjustment cam. https://vimeo.com/120643685

This thread has a few more links in post 54 showing RUWI spindle set ups Router Motor

I changed my thinking after starting this thread and decided commercial lifts do nothing except add expense and complicate things.

I have the feeling that the 3-phase spindle motors will soon be replaced by "stepper motors" similar to those used in "brushless" battery-operated tools now becoming common, even on lower-end tools. As with all electric variable speed motors, they work using magnetic attraction or repulsion so the effective transfer of energy is "lossy". You loose power somewhere. Less power is developed at the output shaft than is consumed by the tool. Stepper motors seem to be more efficient than induction motors due to improvements in magnets and materials associated with the armatures.
The main use for stepper motors had been for precision movement control, which they are really good at, but someone worked out that they are also an efficient motor that will happily run power tools and other continuous loads. The age of the 3-phase induction spindle motor and VFD could be coming to an end? My forecast is that, sooner than later, all power tools that now use "universal" brush motors will be replaced by "brushless" motors which would be smaller and lighter, quieter and more efficient than what is common today.

Stepper motors and DC power tool motors are different things. Yes they are both brushless dc motors but the stepper motor has it's full rotation divided into a number of steps (hence the 'stepper') that can be precisely controlled.
Induction motors are another thing entirely. You can't replace 3 phase AC induction motors with DC motors. Not without significant expense and a not insignificant amount of electronics. Brushless DC motors are around 90% efficient (according to the manufacturers) 3 phase AC induction motors (modern ones) are 85% to 97% efficient depending on the installation and load. 3 phase AC motors are also very simple. Nothing much to go wrong.
Not saying your prediction won't come true but I can't see it happening any time soon.