Motor circuit

[sparkysim]

Need some advice guys. My boss asked me what I thought about this,
We have been asked to install some recirculation fans in a poultry house. They are all on a triac driven speed control and we are going to run a individual supply to each fan. With a mcb for each fan. What I want to know us could we not run one supply out big enough to run all the fans and run it as a radial into 16a sockets and daisy chain them?

I looked in the regs and could not see anything that said we could not run one supply. But something in my mind tells me we should run individual supplies.

Any advice guys?

 

[netblindpaul]

Minimise inconvenience in the event of a fault.
All on 1 breaker, all go off if the breaker trips.
What is the service level required?

 

[spark 68]

It may be cheaper to run one larger supply/distribution cable and provide local MCB's/switched fuses (fused down so to speak), for each unit with a corresponding smaller radial cable to each unit.

You will need to do a cost/benefit analysis.

 

[sparkysim]

Minimise inconvenience in the event of a fault.
All on 1 breaker, all go off if the breaker trips.
What is the service level required?

Yes Paul that's why we was going to run separate supplies so if one fails the others keep going.

I think the customer just wants cheap as possible!!

 

[netblindpaul]

OK,
Do what the customer wants, and get them to sign the design part of the cert, or a disclaimer, if they won't, do it right and charge them accordingly

 

[sparkysim]

OK,
Do what the customer wants, and get them to sign the design part of the cert, or a disclaimer, if they won't, do it right and charge them accordingly[/QUO

Yup I agree

 

[steveberry11]

How can you ask the customer to sign the design section of a EIC if they have not designed the circuits.
You do not say why the customer wants to save money or there comments on the design.
The method you state is the best allowing for maintenance and discrimination. What would the cocquences be if all fans failed at once and were off for a while.
Rather than asking the customer to sign a disclaimer can you not supply a quote with two options fully explaining both along with the Fault consequences. This will give them an informed choice.
I think that asking the customer to sign a disclaimer is a bad idea and suggests that you know that you are installing something that you know is wrong and passing the blame Over to them.
If I was asked to sign a disclaimer the guys would be on there way pretty quickly.
Work with them and find a suitable solution for them and yourselves

 

[netblindpaul]

Well, the customer is not competent to tell you what to do so if they feel they are then they should carry the can.

 

[Knobhead]

How many fans? Do you already have the VSD?
You seem to be concentrating on the fan units, with one drive supply I would be more concerned about that failing. I personally would be looking to install two or more drives so a failure isn’t catastrophic.
I know it’s not the cheapest option but the versatility makes it worthwhile.

No fans could land your customer in the mire over husbandry issues.

 

[sparkysim]

It's 4 fans and an add on not the main ventilation so can always turn the main ventilation on to cover a failure. It is only used for minimum ventilation. The VSD comes with the kit so we just have to wire it all up.

 

[Marvo]

I vaguely remember there's a set of best practices specifically for ventilation of poultry buildings but I just searched my regs can't lay my hands on it right now. The birds are very sensitive to temperature and air quality. I worked on a similar system a few years ago after a failure of the existing system had resulted in all the birds dying so I would advise caution when designing this kind of system.

If I can find the regs later I'll post again with more specific info.