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240v Braked motor for saw

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240v Braked motor for saw

Postby meccarroll » 31 May 2016, 07:45

Hi all, just to give a bit of background,I currently use a city 619 table saw which is a very capable saw but has no scribe blade. I have some jobs coming up where a scribe blade would be very useful so in the market for an upgrade. I'm looking at purchasing something like a SC3 Panel saw which does have a scribe blade (small footprint too).

The problem is picking up a decent single phase machine (I only have single phase) at the right price.

The SC3 saw has a 2,2Kw 3hp.
1.
One option is to purchase an existing 240v panel saw but some machines may not be braked so I was wondering how difficult it is to replace an existing un-baked single phase motor with a brake done and where would you purchase a new braked motor from.

2.
Another option would be to purchase a three phase machine and convert it to single phase again by replacing the motor for a braked motor.

Anyone know what the cost may be and what is needed, suppliers.

I am aware that phase converters exist but not wanting to look at that at the moment.

Any input would be appreciated.

Mark
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Re: 240v Braked motor for saw

Postby 9fingers » 31 May 2016, 09:34

Hi Mark,

I think you will have extreme difficulty (= expense) finding what you want.
Fundamentally, the requirement for braking comes from the need for machinery in trade shops to come to a halt in under 10 seconds and trade shops more often than not have 3 phase power.
So the market for single phase braked motors is very small.

For now you have ruled out converters. You should know that if you do consider them in the future, they will not provide any braking in their own right.

Braking of three phase motors is achieved in one of three ways I can think of

1) a DC injection module fitted between the 3 phase supply and the motor.
2) an electromagnetic (usually dc) disc brake fitted on the motor itself with a separate control module.
3) By use of an inverter which can be programmed to give specific acceleration and deceleration.

I've not experimented with an injection brake and a converter but could foresee some problems with a static converter leading to the need for a rotary converter and an injection brake

I don't know the SCM machine but many saws fitted with scribing blades use separate motors for the two blades thus potentially compounding the problem in your search for single phase braked motors.

In my book inverters are the ideal solution to this requirement.

hth

Bob
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Re: 240v Braked motor for saw

Postby meccarroll » 31 May 2016, 11:35

9fingers wrote:Hi Mark,

I think you will have extreme difficulty (= expense) finding what you want.
Fundamentally, the requirement for braking comes from the need for machinery in trade shops to come to a halt in under 10 seconds and trade shops more often than not have 3 phase power.
So the market for single phase braked motors is very small.


In my book inverters are the ideal solution to this requirement.

hth

Bob


Cheers for the input Bob,

True most larger joinery shops run three phase machines but all new workshop machines are braked now regardless of phase ( Panel/bench saws at least). The market is a lot bigger than it was years ago, a lot of diy woodworkers have a better equipped workshop than I worked in when I was an apprentice (1976)......Steel circular bench, 16" thickness planer, 6" jointer planer and a wolf drill used with a morticed attachment, that was it! Yep the workshop was naff!

Fitting a braked single phase motor is just another option I'm looking at rather than being confined to buying three phase with inverter or overpriced single phase braked machine.

The MiniMax SC3 does come in single phase and runs both main and scribe from one motor. It's primarily aimed at the smaller workshop that wants a panel saw but without the huge footprint that many of the three phase giants have.

I have looked around and Axminster do a range of (what they call trade panel saws) 240v (braked) but I'm in the trade and not convinced they will stand up to trade use. My Kity 619 does a good job at converting 2" and 3" timber but with no scribe blade it's a bit limiting. That is why I like the MiniMax SC3......it's a pro machine that has a scribe and should do the job.

Maybe I'll have to go the inverter way if I want a SC3 with trade capabilities. If I do could you recommend an inverter that is capable of running a 3-4hp motor. I know there are a lot of inverters advertise but I really don't know enough about them to make the right choice.

Regards Mark
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Re: 240v Braked motor for saw

Postby 9fingers » 31 May 2016, 13:30

Hi Mark,

A single motor solution as per minimax will make life easier. I too have noticed mid market machines now offering braking to attract the trade as well as being a possible selling point to amateurs.
I think this is being implemented in the control gear and I need to up to speed (or should that be down to speed? :lol: ) with how they are doing it. Certainly there a quite few bodge solutions being put on brush motors to give braking and in some cases slow start features.

If you end up down the inverter route then there is no point in having an inverter with greater output than you need, it will only have to be programmed down to match the motor power otherwise it will not protect the motor properly. so a 2.2kw one will be ideal. You don't need a fancy vector one either. Once we know the motor type (single or dual voltage) I can sort you out with an inverter either from my stock or guide you with one from another source.

hth
Bob
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Re: 240v Braked motor for saw

Postby meccarroll » 26 Nov 2016, 13:06

9fingers wrote:Hi Mark,

A single motor solution as per minimax will make life easier. I too have noticed mid market machines now offering braking to attract the trade as well as being a possible selling point to amateurs.
I think this is being implemented in the control gear and I need to up to speed (or should that be down to speed? :lol: ) with how they are doing it. Certainly there a quite few bodge solutions being put on brush motors to give braking and in some cases slow start features.

If you end up down the inverter route then there is no point in having an inverter with greater output than you need, it will only have to be programmed down to match the motor power otherwise it will not protect the motor properly. so a 2.2kw one will be ideal. You don't need a fancy vector one either. Once we know the motor type (single or dual voltage) I can sort you out with an inverter either from my stock or guide you with one from another source.

hth
Bob


Bob I've still not upgraded yet as my kity panel saw is still doing it's job. I am, though, still looking and have seen a three phase SCM Mini Max SC3 on fleebay. I'm not 100% sure if I'm going to go for it but I'd need an inverter if I did. Here is the label on the side:

Image

Is there enough information on it to decipher the type of inverter needed? Any chance you could point me to where I could buy an inverter and the likely cost.

I'm not 100% sure what I'm going to do right now regarding upgrade as I've recently set up my kity and it's performing really well but I'd still like a saw with a scoring unit.

Mark
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Re: 240v Braked motor for saw

Postby 9fingers » 26 Nov 2016, 14:07

Hi Mark,

I need to see the motor plate itself. The machine plate is saying it is configured for 415v (normal for UK) but I need to know if the motor is capable of delta connection.

Delta connect makes the inverter straight forward although there are less models around above 3hp. If we are stuck with star connection then you will need one of my specially modified types of inverter that will convert from your 240v single phase supply to 415v three phase. All very doable and I did one for someone on UKW only this week.

So you can safely proceed with a purchase if you want to in the knowledge that I can get you up and running whatever the motor type is.
I've got a 4hp Vector of the type needed for voltage conversion on the shelf, un-modified as yet but that is possibly more sophisticated than you need for a saw as it is designed for top performance at low speed so is right for lathes & mills etc
As soon as you have purchased your saw and we know exactly what you need, I can look out for a suitable model for you. Prices will vary with how cheaply I can get the donor for and how much refurbishment it needs. I'm not out to profit from forum members just cover my costs and a drink. You get 30 day money back if you are not happy with performance and 12 months repair/replace warranty and support for as long as I'm sane enough to give it. I've only had one back to replace a fan that died. No one has complained about the service yet! :lol:
Once we get into details and costs etc can we take this off forum please by email to motors@minchin.org.uk

hth

Bob
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Email:motors@minchin.org.uk
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Re: 240v Braked motor for saw

Postby meccarroll » 26 Nov 2016, 15:06

9fingers wrote:Hi Mark,

I need to see the motor plate itself. The machine plate is saying it is configured for 415v (normal for UK) but I need to know if the motor is capable of delta connection.

Delta connect makes the inverter straight forward although there are less models around above 3hp. If we are stuck with star connection then you will need one of my specially modified types of inverter that will convert from your 240v single phase supply to 415v three phase. All very doable and I did one for someone on UKW only this week.

So you can safely proceed with a purchase if you want to in the knowledge that I can get you up and running whatever the motor type is.
I've got a 4hp Vector of the type needed for voltage conversion on the shelf, un-modified as yet but that is possibly more sophisticated than you need for a saw as it is designed for top performance at low speed so is right for lathes & mills etc
As soon as you have purchased your saw and we know exactly what you need, I can look out for a suitable model for you. Prices will vary with how cheaply I can get the donor for and how much refurbishment it needs. I'm not out to profit from forum members just cover my costs and a drink. You get 30 day money back if you are not happy with performance and 12 months repair/replace warranty and support for as long as I'm sane enough to give it. I've only had one back to replace a fan that died. No one has complained about the service yet! :lol:
Once we get into details and costs etc can we take this off forum please by email to motors@minchin.org.uk

hth


Bob



Thank you Bob. Just took a look on fleebay and it's gone but it may just have run out of time. If I find one I like I'll be in contact via email.

Thank you very much Bob.

Mark
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Re: 240v Braked motor for saw

Postby 9fingers » 26 Nov 2016, 15:21

You are right, looking at the completed listings, that machine did not sell but unless you were in contact with him during the auction period, it is devils own job to get hold of the sell. Ebay are very tight like that.
You might have to wait till it relists. then establish a contact by asking a question then you will be able to follow him up.

Good luck

Bob
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Email:motors@minchin.org.uk
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