Help on isolation switch fit two circuits/power supplies

[Nathcr3708]

Thank you.
Since plugs are 30Amp that are used for large appliances maybe the 32A I have will be more better I plan to fuse each component anyway. In regards to vfd input since that side is AC would a 16A AC contact with a 18Amp thermal relay be ok to use or would you use the thermal overload on something else I.e dc related? also using the same contact would it be good practice to put a estop onto that contact or would the dc side contact connected to the breakout board be best to put all my estops there as shown in the diagram from centroid?
My electrician calculated the ampage with the manual to the vfd and counting in the spindle she suggested 16A even though the manual said 13A.

I have the relay extension board as well but 10A relay that I'm not sure I should use for the vfd that's why I'm putting in a contact AC side with thermal overload or would the 9A contact on dc side be better using the overload relay this is the only bit that confuses me.

What are you fusing you components with breakers or fuse holders and what makes are a reasonable priced?

What do I do to make my control board run my 12v cooling system start with the spindle so there's no need to worry about having to manually doing that?

What breaking resistor should I use for the vfd?

Thank you for the help it's becoming much clearer I think I was over thing a lot.

[centroid467]

I can answer two of these:

There should be formulae to calculate the required braking resistor or a table listing the values in the VFD manual. Depending on what series of VFD, it might have the braking resistor built in.

You can assign one of the output relays to "SpindleCoolingFan" and it will turn on and off with the spindle.

[Nigelo]

I just need to understand how with one circuit can I dedicate seperate parts I.e the control unit the drivers and all equipment from the vfd and spindle. How would you go about doing this?

Suggest using MCBs on the AC supply side inside each cabinet with suitable current rating for each component(s) you wish to protect. Following link shows 2 pole MCBs with current ratings from 1A to 20A
https://uk.rs-online.com/web/c/fuses-ci ... kers/mcbs/

Why should I put the vfd in a seperate box I've seen almost all enclosures online with the vfd in the same enclosure.

In 2 words, electrical noise. VFDs are notorious for generating noise and as you will see on this Forum there are many examples where lost steps and other related problems have been traced back to VFDs especially cheap Chinese items. "Other people have done it that way" does not cut it unfortunately.

Do a search on this Forum and find just 1 thread where it is actually "recommended" to place a VFD Noise Generator in the same cabinet as the control where you can avoid it. I have not said it cannot be done, "not insurmountable" being the words I used.

Also don't forget single point earthing within cabinets and that all control wiring should be shielded and earthed/grounded in any event - I only use CY multi-core cables for this purpose.

Good luck with your project

[Gary Campbell]

Why should I put the vfd in a seperate box I've seen almost all enclosures online with the vfd in the same enclosure.

In most cases, I do exactly what you refer to. VFD in the control box. No problems, as I have an oscilloscope, I stock various sizes and types of line reactors, and EMI filters AND I use Hitachi, Yaskawa and Delta (AD) branded high quality VFDs. Even then, in some cases the higher priced units will cause EMI in the system.

The advice not to do this is sound to the DIY builder as they:
Usually purchase lower cost, lower quality Asian VFDs
Due to inexperience, usually don't realize when an issue is due to EMI
Usually don't have the knowledge and equipment to detect the source of EMI
Seldom have components on hand to eliminate the EMI

[tblough]

I have 4 machines with VFDs in the control box. Two are Yaskawa, one is a Baldor, and one is ABB. As Gary says, the amount of noise radiated from the VFD is very low on name brands. And, I'm using $6/ft shielded inverter cable, properly grounded, for the motor connections.

You don't have to house the VFD in a separate cabinet. You DO have to employ good practices.

[ShawnM]

You don't have to house the VFD in a separate cabinet. You DO have to employ good practices.

Very well stated Tom. I see so many problem builds where builders use unshielded cable everywhere and wonder why they have noise. I also put my VFD in the same cabinet as the rest of the system. If the system is built properly with properly shielded cable where needed and wired using best practices you wont have any issues.

I've had people freak out when I tell them good quality, shielded VFD cable is $5 a foot but they have no issues buying a second cabinet just to house the VFD with unshielded, crappy wire, go figure.

[Nathcr3708]

Thanks for the advise guys.

I've already gor shielded cable I'm using SY cable that should do it also in regards to EMI filter I've bought a small RS 20A EMI filter would that cut it or do you think I need a different type?
I am on single phase aswell.
Mine is a Chinese vfd it's a huanyang one so I don't think it has a breaker within it apparently most the Chinese stuff don't. Over time I will be replacing them when I can afford ro spend but I just wanted to get back up and running.

[tblough]

This is the cable that I use - "Servomotor Continuous-Flex Cable" It's gone up a little - 14Ga is now $7/ft, and 10Ga is up to $12.45/ft but still worth it.

https://www.mcmaster.com/products/multi ... lex-cable/

[ShawnM]

I use Southwire VFD cable.

https://cabletechsupport.southwire.com/ ... country=US

[centroid467]

Mine is a Chinese vfd it's a huanyang one so I don't think it has a breaker within it apparently most the Chinese stuff don't. Over time I will be replacing them when I can afford ro spend but I just wanted to get back up and running.

I think you might be able to find a matching manual on the following website if you can find the part number for your VFD: https://www.huanyangvfd.com/download/