Sedwick P/T advise

[mmmm]

Hi all. I'm wondering if anyone is able to help.

Ive recently been given a 3 phase Sedgwick spiral P/T (ive attached photos of the motor plates). Im trying to find the best solution to run this on my single phase supply (my supply to my small workshop is 60A and im happy to make sure nothing else is running whilst I use this). The cost of replacment motors and gearbox is very expensive. I noticed someone post a link to this https://www.jfkelectricalni.com/product/digital-phase-converter-7-5kw-10hp-240v-in-400v-out/ in other threads. Do you think this would be a good solution? or is anyone able to recommend similar products that they've had succsess with? I don't current have any other 3 phase machines, but it is possible that id buy a three phase spindle molder in the future.

Many thanks

Andrew

 

[Spectric]

That digital phase convertor would be a good solution, it is larger than you require but would give you a three phase supply in your workshop which means you can also buy other three phase machinery like a spindle moulder. What you need to do is ensure that your supply cable to your workshop can supply the 40 amps with no more than 4% voltage drop, ie about 9 volts and that the loop impedance is low enough to allow for a type C protective device to operate.

 

[Sideways]

Since one of your two motors is 380-415V only, you can't do this with two ordinary variable frequency drives. The JFK is probably the cheapest as well as easiest solution.
The maximum size of motor that these JFK drives can start when they are powering multiple motors is a lot less than their rated power. I can't remember the spec but maybe 60% of max.
You have two motors and the bigger motor is 3kW. You shouldn't buy smaller than the 5.5kW model. I would email JFK and check before buying.
If you are an electrical novice, I'd seek some help. 415V is much more dangerous than 240V. This is not a project to teach yourself on.

 

[Spectric]

you can't do this with two ordinary variable frequency drives

The item https://www.jfkelectricalni.com/product/digital-phase-converter-7-5kw-10hp-240v-in-400v-out/ is a 7.5 Kw convertor, fixed frequency and when I said it is larger than you need I had not realised the two pictures are of different motors so it will be ok for your two motor sedwick but it would not hurt as @Sideways has said to contact JFK to confirm this convertor will be big enough. Also I would say that unless you are qualified in electrical work that this would be a job for an electrician not only for your safety but they will have the test equipment to validate the work.

 

[mmmm]

Thanks for the advice all. I wouldn't carry out the work myself, and will use a qualified electrician. I was more seeking general advice as to whether the phase converter I linked would be a good solution. I'll email JFK. Do you know if JFK converters are a decent quality or would you suggest another suppliers?

Thanks again Andrew

 

[deema]

@Sideways and I have used / installed / advised on a couple of installs of the JFK converters. They were great and worked really well. They allow speed control and can control multiple motors unlike a standard inverter. Would I use them again, sure, not an issue. A good solution to enable you to run not only the PT but potentially other 3 phase kit.

There are a few other solutions however,
1. Get 3 phase. It’s now not as horrendous cost at it once was as you no longer contribute to the infrastructure (April 1st last year, I know the date of the change is wonderful). A good option if your considering having say an electric cars and or air / ground source heat pumps.
2. Convert it to single phase. The motors are IEC marked so will be standard mount configuration. I can’t see the frame size of the smaller motor, but the 3KW motor is a B3 100L frame which is bog standard. This will definitely add value to your PT. Not sure why the main motor is 3KW unless you have the 16” CP machine, the MB is happy with a 2.2KW main motor which is the ‘cheapest’ single phase cap start cap run motor 2800rpm motor you can buy.
3. Possibly a half way house on cost is to swap the 3KW motor to single phase and run the small motor on an inverter if it’s a special. Ie a non standard motor…….that would be very unusual for Sedgwick, all the PT machines I’ve ‘played’ with have had standard off the shelf motors….however….although I’ve played with a number, there is always a the potential of a variant I haven’t come across.

 

[mmmm]

Thanks @deema. Im not sure option one is viable as I live in the middle of nowhere. Im very isolated and probably have a run of at least 100 electricity poles just to supply myself and my nearest neighbour. I do however have a pole very close to my house (Ive no idea if this is a good or bad thing, im pretty ignorant when I come to this). I'll certainly look into the other options.

Thanks

Andrew

 

[Spectric]

They allow speed control and can control multiple motors unlike a standard inverter.

I think when using this convertor to control two motors then you cannot have variable speed but then you don't really need that and would be better having three phase available to several machines, ie the spindle moulder.

Im not sure option one is viable as I live in the middle of nowhere. Im very isolated and probably have a run of at least 100 electricity poles just to supply myself

That suggest a TT type electrical supply where the protective earth is not provided, to get three phase could be expensive depending how far the transformer is from your property so the convertor is your best option.

 

[mmmm]

I did contact national grid to get a price just incase it is feasible. JFK were helpful and informed me that id'd also need a sine wave converter to accommodate the DC brake. I'm not quite sure what that means.

Thanks

Andrew

 

[Spectric]

need a sine wave converter to accommodate the DC brake.

The Dc brake will throw a spanner in the works, you will need a pure sine wave convertor which will add some money to the unit. The Dc brake applies a DC current to the motor which will slow it down to a stop, you can adjust the amount of current injected.

Did JFK suggest one of these

https://www.jfkelectricalni.com/pro...re-sinewave-digital-3-phase-converter-7-5-kw/

 

[Sideways]

The planer may not have a DC brake and for home or single person business use, isn't required to have one.
If you post up a photo of the planer viewed from the front, we may be able to tell.

 

[mmmm]

Thanks again all, you've been more than helpful and patient. Ive attached a photo of the planer. He suggested something similar to the one you linked @Spectric, he also said it would be possible with the original digital phase converter and a seperate 16A sine wave converter. I guess it would be possible to just remove the brake if it's not needed (I dont know if this a possibility.

Andrew

 

[deema]

That’s the very latest version of Sedgwicks PT, lovely machine. It has a DC injector that causes the motor to brake. Most sparkys would not know how to remove the brake function and personally I wouldn’t want it disabling. @Sideways is right you don’t have to have it for personal use, but the sparky would be doing you a disservice in taking it out and potentially making themselves liable if you injured yourself.

For that machine if it were mine I would be looking ant either getting 3 phase or the JFK digital phase converter.

 

[Sideways]

Yup. That has a DC brake on the front.
Don't take it off.

 

[Spectric]

I would agree that it being three phase then it would have required the brake as it would have been used in a business workshop and so really why remove something that you are lucky to have so just buy the big pure sinewave convertor and get woodworking.

 

[mmmm]

Thanks for all the good advice. I wait to hear back regarding the cost of installing 3 phase, if that's very prohibitive I'll go down the phase converter route.

Andrew