Winding myself up

[cooper1203]

my lathe has a 1/2 hp motor single phase but no capacitors. (yes it runs)

For the switching gear i want a remote on/off, a contactor with an overload pack, an emergency stop button and a no volt release. Question is what ratings do i need. doing some calculations (hp to watts and dividing by the voltage) i get just over 1.6 amps. However google says anywhere between 1.5 and 9 amps. Next question is what will the start up current be and what time delay do i need on the overload pack so it doesnt see it but low enough rating so it does its job.

ps forgot to say all calculations are baised on 230v

 

[markba633csi]

You have more choices to make: Do you want a high voltage remote or low voltage (low is safer)
Do you want a fixed circuit breaker protection or an adjustable device? (the former is simpler and likely quite adequate for a 1/2HP)
Sounds like you probably want a transformer-powered system with a latching contactor

Motor start up currents can be 5 to 8 times the running current; most standard house breakers have built-in delay to account for that
Many motors have internal thermal protection devices

 

[cooper1203]

i dont think the board i have is compatible with adjustable rcd's. although the final setup will go to the fuse board to be honest i was just going to run it off the socket ring main rather than go to all the expense and trouble of wiring it more permanently then deciding i dont like the hobby or im no good at it as im a complete newbie.

i assuming a low voltage remote switch would be used to energize a relay or some other switch to power the motor from the mains but would then need some kind of latching mechanism itself

not sure why i would need a transformer.

the issue is all the local electrical supply shops around me dont understand this sort of stuff. all they are there for is for the sparks to walk in and ask for 1 of x please mate

im probably going over the top with the bits i want but each part is there for a reason to minimize damage or injury

 

[markba633csi]

You probably should post some pictures of your hardware and motor- Is this an ac induction motor or dc?
A low voltage control would need a transformer to step down the mains voltage to something like 24 volts for control
A high voltage control would run mains voltage to the remote switches/buttons and is less safe especially with 230v

Contactors can be wired to be self-latching until power is interrupted, what you call no volt release
This requires a contactor with an auxiliary pair of normally open contacts- a common item in the "sparky" universe

 

[cooper1203]

thats just it all i have is a motor no switch no nothing. i need to go out and get the kit above but dont know the ratings. And as like most things in this country with the great dumbing down that happened late 90's early 2000's and a few other factors there arent any proper shops anymore with knowledgeable staff

sorry meant to say the motor is single phase 4 pole ac motor

 

[pontiac428]

I agree with Mark. The low voltage control system is the way to go, and it makes interlocks and interrupts so much easier to implement. It's different from your household distro panel, so you'll need to source your kit from an industrial/automation controls vendor. It's usually DIN standard. It's not expensive vs. the sparky supply store. For the main motor circuit rating, search by your motor. Single phase motors have high inductance/inrush. My 3 phase 8 hp lathe motor (Weg make) is famous for high inrush, it draws 24 hp for about 1.5 seconds to start depending on what spindle gear I'm in. It's how a vacuum cleaner being switched on can trip a breaker that already has a partial load on it. You'll have to look up the motor data sheet or test it with a load meter in situ.

 

[markba633csi]

I would suggest a visit to Aliexpress!
The supermarket of electrical goodies-- and so easy on the pocketbook
I sound like an advert LOL

Would you be wanting to have this motor be easily reversible by means of a remote switch? That's getting into some complexity

 

[cooper1203]

I would suggest a visit to Aliexpress!
The supermarket of electrical goodies-- and so easy on the pocketbook
I sound like an advert LOL

Would you be wanting to have this motor be easily reversible by means of a remote switch? That's getting into some complexity

Prob not for the time being as my chucks are screw on to the lathe nose so until i understand the cutting forces and other things i can see me screwing up and the chuck come flying off if i try and run it in reverse

 

[markba633csi]

Usually that feature is reserved for lathes with backgears for slow thread cutting, for metric threads where the half nuts must stay engaged.
The spindle is reversed to move the cutting tool back to the starting point. We are talking spindle speeds less than 100 rpm; just rotational forces, not cutting

 

[Firstram]

I have this magnetic starter on on 2 table saws and a bandsaw, it’s been flawless.

Amazon

It says 220v but, I think the coil is 110v. You can wire in an Estop or build a paddle to make the stop button much larger.

There are several other options to choose from but I have only used this one.