Started a new project and a question

[Kingcha]

First the question.  Since I am still learning I often turn off my 10hp electric motor while I decide my next action, sometimes its for only 3-5 minutes.   Would it be easier on the motor to just leave it on?

Started the solar kiln today.

A few of the beams cut for the kiln

 

The floor framing is done

  

 

Hey on another note, am I the only one that has a problem with the last cut of a log.  Yeah I have ruined a blade or 3.   I gotta slow down and measure twice I guess.

I have to set up another temp building for dying lumber.   I would be sawing more if I just had more space.   I am looking forward to sawing for others so they can take it with them.   :D

I had more questions but they are not coming to me right now.  Thanks for listening.

[justallan1]

I don't know the right answer for you, but I know that the two bands that busted on me were while it was running at full speed sitting out of the log. I don't know why that would happen like that, but it did.
As for turning on and off an electric motor, I think it would affect you utility bill the most, granted you probably don't want to be doing it all day.
When I get down to the last board and if for what ever reason it ends up an oddball number I flip the board rather than trying to clamp a thin piece and then just measure off of zero.

Allan

[customsawyer]

I don't run a electric mill but have been looking at switching to one. I discussed this very thing with Sparks as when I load a new log I usually have to get on the loader so the mill would not be cutting for 2-3 min. Sparks informed me that the WM electric motors have a soft start on them so they don't draw the high amps at start up. He said if it was him he would turn the mill off between logs to save on blade life.

[Kingcha]

Thanks Custom.

Yeah loading a new log I would always turn it off but sometimes such as when I'm just turning the log I turn it off and then I realize it was only off for 2-3 minutes.  And by the way you always disengage the blade when your done cutting so the blade would not be turning(cutting) in between cuts.  Yes it is a real soft start.   One 1 hp table saw starts harder.

[WoodenHead]

I don't have an electric mill, but I do have some knowledge of electrical things.  Soft starts usually have a limit to the number of starts you can do in a given amount of time (often not that many).  If you can disengage the blade and leave the motor running, I think that would be the easiest on your equipment.

[bedway]

I built my mill so i can cut down and end up with a one inch thick board at my minimum depth.  Then i drew up a scale in 1and 1/8 increments up to the max my mill will accept. Example,


etc.
6 3/4
5 5/8
4 1/5
3 3/8
2 1/4
1 1/8

When i flip a log after an opening cut and the log happens to be 7 inches high i know if i bring the head down to 6 3/4  and cut down from there ill end up with a 1 inch board.

[beenthere]

Soft starts usually have a limit to the number of starts you can do in a given amount of time (often not that many).

Interesting... how is the limit determined?

[WoodenHead]

Soft starts usually have a limit to the number of starts you can do in a given amount of time (often not that many).

Interesting... how is the limit determined?

It is usually specified by the manufacturer and may be based on full load starting.  In the case of a sawmill the load is light upon startup. 

[beenthere]

Soft starts usually have a limit to the number of starts you can do in a given amount of time (often not that many).

Interesting... how is the limit determined?

It is usually specified by the manufacturer and may be based on full load starting.  In the case of a sawmill the load is light upon startup.

So are you saying the mfg. has a built-in failure? Or if one exceeds the limit (number of starts in a given amount of time) then what happens? Is there a counter keeping track of startups?

Sorry to ask more ??'s, but I'm missing the point you made in the first quote.

[drobertson]

I got to run an lt70 a while back, it had the soft start 3ph 25hp, it did not have an auto clutch, so if the motor is on the blade is running, I was not a big fan of this,  I think I like to see where the motor is running but not the blade at times where there is a pause in sawing,  david

[WoodenHead]

Hi Beenthere,

Sorry for not explaining further, I was at my son's last soccer game for the summer.   

I'm not sure if this link is allowed on the forum or not, but here is a link to a formula for calculating the number of starts you are allowed per hour:

www.softstartuk.com/downloads/faq/rvs-dn.pdf

I don't believe this is a universal formula, but it gives you an idea of what is involved.  Essentially you'll overheat the softstart if you start and stop too many times in an hour.  There is nothing to prevent you from doing so, except maybe some built in over temperature safeties.  Depending on the load you are trying to start some softstarts are only rated for 4-5 starts per hour.  That's not much when you think of how you might be using an electric motor in a sawing application.  Fortunately, as I mentioned, starting a mill is not the heaviest load, so you can probably get away with more.

Hopefully this helps.

Personally I would still want a clutch on an electric mill.  ;)

[Kingcha]

Personally I would still want a clutch on an electric mill.  ;)

Mine does and I am very happy to have it. 

Thanks all for the input, I will have to work on just leaving it on.

[Ianab]

This duty cycle thing would be down to the design of the individual soft start units.

It would obviously be possible to design one with enough heat sinking and cooling that could stop and start the load as often as needed. But that would cost more, and in most applications it would be unnecessary.

Manufacturer should be able to tell you if there is a limitation like that on a machine. On a relatively small load like a portable sawmill, that is expected to start and stop quite frequently it's likely the starter is rated for as many starts as needed?

Ian

[Kingcha]

Thanks Ianab.....I will have to check the specs in the manual if its in there.

A follow up to bedway, I made charts for cutting cants that help a lot.  Still cutting the last 1 inch board I have made mistakes clamping to close(not good on the blade)  I have since found some different ways to clamp and with time and practice I hope not to hit my clamps or log dogs again  :D

My charts....Steal them if you want.


  

  

 

[Migal]

My mill is not Electric  8) that being said I work at a plant with plenty of three phase electric motors that cycle on and off as needed with no problem only a few have soft starter's so if the overloads are correct it will be more about your electric bill as my granddad always said leaving a light on is cheaper than turning it on and off every five minutes and he was a bonafide electrician.  8) The plant has deep pockets and no electric bill Go Figure
Note: always let it come to stop before cycling so if your faster than the perpetual motion smiley_horserider leave it on IMO

[Happycamper]

Kingcha,
  You are well on your way to completing your initiation with a clamp and dog to your credit. Looks like you are very much enjoying the new mill.
                                Jim

[Martha White Nelson]

Nice pictures!!!  Have a great day!