Low speed switch on

chrism · Post by **chrism** » Wed Nov 07, 2012 11:35 am

Hi All,

Why is it advised not to switch on/off the SS when the speed control is set to high speed? Is it a worry over mechanical stress or over the current draw at startup?

I must admit that I have inadvertently switched off / on when set to high speed with no (as far as I can tell) ill effects.

In the UK we use 230 volts with individual outlets rated to 13 amps so I don't believe that current draw would be a problem, I don't get the dimming lights on startup I have seen in some you tube videos when the SS is turned on.

terrydowning · Post by **terrydowning** » Wed Nov 07, 2012 11:41 am

When the SS was built and even now in some cases. 110 Volt 15 amp outlets were the norm. If you're using 15 amp 110 volt outlets , then it is a good idea to lower the speed before shutting down so start up draws less power. Some also consider this a safety issue. (Read the thread on removing old band saw tires for what happens to band saw tires when run at high speed.)

I use a dedicated 20 amp 110 volt circuit and I keep the SPTs disconnected when not in use, so this is not generally an issue for me.

You should be OK on the 230 Volt system you have regarding electrical load just be mindful of any SPTs that may be connected and other safety aspects of whirring blades at high speeds.

chrism · Post by **chrism** » Wed Nov 07, 2012 11:50 am

Hi Terry,

Good point re the Spts. Like you I disconnect mine when not in use.

Chris

JPG · Post by **JPG** » Wed Nov 07, 2012 11:57 am

chrism wrote:Hi All,

Why is it advised not to switch on/off the SS when the speed control is set to high speed? Is it a worry over mechanical stress or over the current draw at startup?

I must admit that I have inadvertently switched off / on when set to high speed with no (as far as I can tell) ill effects.

In the UK we use 230 volts with individual outlets rated to 13 amps so I don't believe that current draw would be a problem, I don't get the dimming lights on startup I have seen in some you tube videos when the SS is turned on.

Since my goldie also has a 230v motor I have the same experience as you.

The historical reason is that dwellings back in the '50's' typically had 15A
branch circuits. The startup current surge at higher speeds takes longer than starting up at slower speeds. A time delay fuse(remember those?) was needed to prevent it being blown.

Today breakers are more common and their inherent delay(thermal) makes the recommendation less relevant.

However the longer the turn on surge, the warmer the motor becomes, so frequently starting and stopping will add to the temperature rise.

I do not think you have reason to be concerned when using the higher voltage source. I have not attempted to do the slow/off dance, but with the new steel sanding disc, startup times can get long(inertia).

Large workpieces on the lathe can also cause delay.

When sawing or routing etc.(higher speed operations) lower mass devices will have much smaller inertia.

dusty · Post by **dusty** » Wed Nov 07, 2012 12:20 pm

In my opinion, this talk about inadequate power to start the Mark V at high speed is a bunch of bunk - unless you have inadequate wiring (and or primary power) into your shop.

In a shop wired properly with a 15 amp 110 vac service, a properly maintained Mark 5/V will start at high speed with no problem at all. If it does not, there are problems that need to be resolved.

Do not shrug your shoulders and walk away thinking that it is normal. It is not. I have done a video that is on uTube that shows very clearly that the Mark V is NOT STARVED FOR POWER during a "high speed" start.

The power outlets to my two Mark vs are 14ga, 15amp, 110vac circuits.

terrydowning · Post by **terrydowning** » Wed Nov 07, 2012 12:58 pm

But if they are on a branch circuit, good luck.

Try this on the same 15 amp branch circuit.

turn on shop vac.

turn on incandescent lamp.

turn on shop smith and watch the light dim. Load on start up can be an issue if you're not paying attention. There are a lot of people that don't understand how electricity works and assume I must have enough power because I have available outlets.

Most of the people on this forum would of course wait to turn on the shop vac until after the SS gets up to speed or have it on a different circuit. So this is not much of an issue on modern wiring.

Go back 60 years and well, you get the idea.

Personally, after having lived in England, I would prefer our national electric to be 230 Volt with lower amperage as it is more efficient and safer.

dusty · Post by **dusty** » Wed Nov 07, 2012 3:03 pm

Yes, I agree. I do operate my Mark Vs on dedicated circuits. That is to say, there are no other items drawing power simultaneously with the Mark Vs.

charlese · Post by **charlese** » Wed Nov 07, 2012 4:07 pm

chrism wrote:Hi All,

Why is it advised not to switch on/off the SS when the speed control is set to high speed? Is it a worry over mechanical stress or over the current draw at startup?...

This warning could be a safety issue. You don't want to get a surprise next time you power up. You don't want the headstock to power up to high RPM when you have a lower speed accessory attached. Let's say the lathe or the band saw. Therefore the caution to run the speed down to slow before turning off the power switch.

chrism · Post by **chrism** » Wed Nov 07, 2012 4:48 pm

terrydowning wrote:But if they are on a branch circuit, good luck.

Try this on the same 15 amp branch circuit.

turn on shop vac.

turn on incandescent lamp.

turn on shop smith and watch the light dim. Load on start up can be an issue if you're not paying attention. There are a lot of people that don't understand how electricity works and assume I must have enough power because I have available outlets.

Most of the people on this forum would of course wait to turn on the shop vac until after the SS gets up to speed or have it on a different circuit. So this is not much of an issue on modern wiring.

Go back 60 years and well, you get the idea.

Personally, after having lived in England, I would prefer our national electric to be 230 Volt with lower amperage as it is more efficient and safer.

Agree entirely Terry about people not understanding the basics of how the electrical system works, UK outlets are normally rated at 13 amps on a ring circuit, the total number of outlets is, in theory, unlimited but the total rating for the ring is normally 32 amps, if higher loads are anticipated in an area then extra rings would be laid down or a radial circuit could be used to supply a specific item ie a cooker, welder or shower which you might expect to exceed 13 amps then the only limit is the service limit to your premises, in my case 80 amps.

Anyway, from all the responses it would seem I don't have to worry about starting at high speed, it will certainly be more convenient when using the saw or router. Thanks again, everyone, for the info.

Dusty, thanks for the link to your video, very informative.

Chris

JPG · Post by **JPG** » Wed Nov 07, 2012 8:06 pm

chrism wrote:Agree entirely Terry about people not understanding the basics of how the electrical system works, UK outlets are normally rated at 13 amps on a ring circuit, the total number of outlets is, in theory, unlimited but the total rating for the ring is normally 32 amps, if higher loads are anticipated in an area then extra rings would be laid down or a radial circuit could be used to supply a specific item ie a cooker, welder or shower which you might expect to exceed 13 amps then the only limit is the service limit to your premises, in my case 80 amps.

Anyway, from all the responses it would seem I don't have to worry about starting at high speed, it will certainly be more convenient when using the saw or router. Thanks again, everyone, for the info.

Dusty, thanks for the link to your video, very informative.

Chris

Do pay heed to what Charlese and Terrydowning said.

Dusty, try that 'test' with a steel sanding disk attached.