# Speed Controllers and soft start motors



## kevinrf (Oct 11, 2012)

Virtually all router speed controller ads place the caveat that they will not work with routers having electronic speed control and those with soft start motors. I have learned, somewhat, why that is; at least the electronic speed control conflict.

I have a Hitachi M12V with has both the soft start motor and electronic speed control. However the electronic speed control has become wonky and I have read that it can be removed and the switch wiring being directly attached to the motor wiring effectively rendering the router a single speed at top rpm. I am considering this option as a new electronic speed control unit is rather pricey for an old router, however venerable.

That being the case, does the electronic speed control, create the soft start? If so, is there any reason an external variable speed control would not then work?

I already know that the external units are glorified rheostats and not an electronic speed control as with the M12V or other such routers (the PC 7518 speed control is not electronic and also a glorified rheostat, interestingly enough). I am confused as to how the "soft start" is created in the router and how to make it accept an external speed control.


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## Dmeadows (Jun 28, 2011)

They're all "electronic". Some have a tach feedback to keep the speed constant, some don't. The softstart feature is in the speed control module as well, so removing the speed control from the circuit also disables the softstart. 

The external speed controls are electronic(triac) also, but there is no way to feed back tach info from the router for constant speed.


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## neville9999 (Jul 22, 2010)

Dmeadows said:


> They're all "electronic". Some have a tach feedback to keep the speed constant, some don't. The softstart feature is in the speed control module as well, so removing the speed control from the circuit also disables the softstart.
> 
> The external speed controls are electronic(triac) also, but there is no way to feed back tach info from the router for constant speed.


Kevin I have to build one that has been bought as a kit, I would have been happy to give the retail ones a go but the ones from the USA are 110volts and the ones from the UK are only 8amps so no good for my 22oo watts, from what I see they are all a rheostat's, the kit I have comes from Australia's Jaycar Electronics "KC5478 Delux 10amp Mains motor speed controller kit" and it is 240volts, the thing that they say about it is that it can soft start at near zero speed and then run up to full speed on any brushes type motor but it won't work on induction type motors, from what you have said then I imagine that you are correct, that if you disable the built in speed controller then your old router will just be a normal brushes type motor running at full speed so it should then be obedient to being controlled by an outside source, were I in the USA then I would be happy to give one of the commercially available speed controllers a go as they look fine to me. NGM


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## mgmine (Jan 16, 2012)

Kevin I did what you are saying with my Hitachi M12V and it works,the variable speed control does not create a soft start. If you go this route the best price is from Harbor Freight.


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## Dmeadows (Jun 28, 2011)

neville9999 said:


> Kevin I have to build one that has been bought as a kit, I would have been happy to give the retail ones a go but the ones from the USA are 110volts and the ones from the UK are only 8amps so no good for my 22oo watts, from what I see they are all a rheostat's, the kit I have comes from Australia's Jaycar Electronics "KC5478 Delux 10amp Mains motor speed controller kit" and it is 240volts, the thing that they say about it is that it can soft start at near zero speed and then run up to full speed on any brushes type motor but it won't work on induction type motors, from what you have said then I imagine that you are correct, that if you disable the built in speed controller then your old router will just be a normal brushes type motor running at full speed so it should then be obedient to being controlled by an outside source, were I in the USA then I would be happy to give one of the commercially available speed controllers a go as they look fine to me. NGM


The electrical component that the speed control knob physically turns is a potentiometer or rheostat if you will. Probably rated 5 watts at most, maybe less. It would self destruct if used to control the router directly. It controls a triac, which in turn controls power to the motor. The pot(rheostat) is not the only component in your kit, right?


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## Willway (Aug 16, 2012)

Kevin you can look for a DC speed controller(SCR not Triac) w/feedback and ramp control which is an adjustable soft start. All power tools with brushes are universal ac/dc motors.These are a little tricky to set up as most have a ramp adjustment for soft start, and a max speed and feedback adjustment for for the load. As it senses the load it will automatically increase the power to the tool. Check the surplus electronics outlets, and be sure it is rated MORE than your router amperage. The price used to be around $80. I know they work because I have some in my shop and I have one set up in a box with outlets for a drill, sander or whatever you plug in it.

willway


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## Dmeadows (Jun 28, 2011)

Willway said:


> Kevin you can look for a DC speed controller(SCR not Triac) w/feedback and ramp control which is an adjustable soft start. All power tools with brushes are universal ac/dc motors.These are a little tricky to set up as most have a ramp adjustment for soft start, and a max speed and feedback adjustment for for the load. As it senses the load it will automatically increase the power to the tool. Check the surplus electronics outlets, and be sure it is rated MORE than your router amperage. The price used to be around $80. I know they work because I have some in my shop and I have one set up in a box with outlets for a drill, sander or whatever you plug in it.
> 
> willway



If you are not familiar with DC controllers, thats probably not a good way to go. Some are controlled by a simple pot/rheostat(Still should be the right resistance rating for that controller). Some are controlled from a PWM signal developed external from the controller. Some require a tach pulse from the drive train. Some require a series choke. Some are designed for permanent magnet DC motors, not the universal motors used in routers.

If none of this makes sense to you_ DON'T_ do the DC controller thing! The wrong controller or the wrong type of control can destroy both the controller and the motor in certain combinations!

There is more to choosing an appropriate DC controller than just saying I want a DC controller that will handle 20 Amps at up to 120VDC.

The easiest and cheapest solution, as someone mentioned, is the HF router speed control at $19.95.


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## Willway (Aug 16, 2012)

kevinrf said:


> Virtually all router speed controller ads place the caveat that they will not work with routers having electronic speed control and those with soft start motors. I have learned, somewhat, why that is; at least the electronic speed control conflict.
> 
> I have a Hitachi M12V with has both the soft start motor and electronic speed control. However the electronic speed control has become wonky and I have read that it can be removed and the switch wiring being directly attached to the motor wiring effectively rendering the router a single speed at top rpm. I am considering this option as a new electronic speed control unit is rather pricey for an old router, however venerable.
> 
> ...


Kevin try looking for a KB Electronics kb125 ($72) w/o heatsink, you will need a heatsink(don't forget heatsink compound). I used these little controllers for years, They work and hold up well in industry. That will give you soft start and does have feedback for load control. If you buy new it will come with a manual, if you buy one used the manuals are available at KB Electronics as PDF files. I just checked ebay there are some KB's and others listed, and cheap cheap! By the way universal motors do perform better on DC.

willway


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## Willway (Aug 16, 2012)

Dmeadows said:


> If you are not familiar with DC controllers, thats probably not a good way to go. Some are controlled by a simple pot/rheostat(Still should be the right resistance rating for that controller). Some are controlled from a PWM signal developed external from the controller. Some require a tach pulse from the drive train. Some require a series choke. Some are designed for permanent magnet DC motors, not the universal motors used in routers.
> 
> If none of this makes sense to you_ DON'T_ do the DC controller thing! The wrong controller or the wrong type of control can destroy both the controller and the motor in certain combinations!
> 
> ...


A DC controller is the way I would go, but D is right you have to have some knowledge of what you are doing. I worked in the industry for 50 years and sometimes I forget that other people have not. The KB controller will work but some electrical knowledge is needed.


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## Dmeadows (Jun 28, 2011)

Willway said:


> A DC controller is the way I would go, but D is right you have to have some knowledge of what you are doing. I worked in the industry for 50 years and sometimes I forget that other people have not. The KB controller will work but some electrical knowledge is needed.


The m12v is a 3HP(yes, I know about the accuracy of that claim) The KBIC-125 has a max HP rating of 1.5HP with the heat sink. With the cost of the heatsink(new any way) your close to the price of the OEM part($110.00) and over half the price of a new M12VE or M12V2. Plus you still need and enclosure and misc parts! For that kind of money I would either fix it right, or by a new one and have the warranty. YMMV.


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## kevinrf (Oct 11, 2012)

WOW! That is a lot to chew on. It was helpful to learn about external speed controllers and the actual differences between the two type of "on board" speed controllers. Thanks for the help, guys.


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## Willway (Aug 16, 2012)

Dmeadows said:


> The m12v is a 3HP(yes, I know about the accuracy of that claim) The KBIC-125 has a max HP rating of 1.5HP with the heat sink. With the cost of the heatsink(new any way) your close to the price of the OEM part($110.00) and over half the price of a new M12VE or M12V2. Plus you still need and enclosure and misc parts! For that kind of money I would either fix it right, or by a new one and have the warranty. YMMV.


Kevin D is right again, I was thinking of the VE which is only rated at 11 amp full load. These little controllers could handle that. They are fused at 15 amp and are rated for 24/7 duty. We had them running true 2HP dc industrial motors 24/7 for years at a time, and they hold up. I have them on hand that is the reason I said that's the way I would go. I would love to find a 3HP+ router with a burned out control to set up and play with. I have several older controllers that are much higher rated amperage.


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## David Hird (Nov 24, 2012)

I support fixing properly or replacing depending on the condition of the rest of the parts of the unit.By doing a home design you could cause more damage than you have already got and at the end of the day you will end up purchasing a new unit and have the cost of purchasing the spares to do the home design.


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## neville9999 (Jul 22, 2010)

Dmeadows said:


> The electrical component that the speed control knob physically turns is a potentiometer or rheostat if you will. Probably rated 5 watts at most, maybe less. It would self destruct if used to control the router directly. It controls a triac, which in turn controls power to the motor. The pot(rheostat) is not the only component in your kit, right?


I fully understand that a speed controller for a Router is more than a glorified light dimmer, I have had a look at my new kit and there are a lot of parts so I will have to just do it quietly and I am sure that it will give my Makita routers a new lease on life. NGM


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