Electric motor amp rating

[Farnx]

Hello
I have just bought a new air compressor and was wondering if the amp rating on the motor name plate would be continuous rating or maximum rating?
this is the stamp plate on my compressor.
449146

I'm mainly asking as i plan to do a shed extension in about 12 months and will be getting a sub board put in for just the shed with dedicated wiring.
but as of right now i needed a new compressor and wanted the bigger Free Air Delivery for air tools and mainly spray painting
As of right now my shed has 10 amp power, Just to make it clear i will not be making adaptors or filing down pins for the 15A compressor plug to fit into a 10A socket.
I want to know if one of the ampfibian adaptors will work.
449147im hoping that the 13A is just the start up load and continuous output would be less than 10 amp.

On a side note i have a 3HP motor on my table saw which is very similar to the compressor motor in terms of rpm but is rated at 7.9 amp
i find it strange that both motors are 3HP but so different in amp ratings.
This is my tablesaw stamp plate
449148


Anyway thanks in advance.

[BobL]

The HP ratings of motors are nominal quantities.
Most motors make variable power output depending on the imposed load.
I have ammeters on most of my gear so ai can see what they are doing and something like a 3HP rated motor will draw about 5-6A free running and then the current drawn by the motor depends on the load imposed onto the motor. On my 3HP TS it draws about 10A when cutting 75mm hardwood and 12A when cutting 4" thick hardwood and of course if I push the wood really hard it trys to draw even more current - up to about 17A!!! where the motor starts to get hot quickly and the thermal cutout kicks in and cuts the power.

When my 4HP compressor starts and theres no back pressure it draws about 7A then as the pressure climbs the current drawn by the motor climbs with it and the current drawn at the end of the cycle is close to 14.5A.
During recharge the current starts at about 10A and goes through to the 14.5A

The Amfibian is not really the way to do this.
The 13A on your compressor will be the maximum current that motor will draw to recharge the compressor and it should really be placed on a dedicated 15A circuit.
Your 10A circuit might well have a 16A CB on it but the problem will be you will be happily doing something drawing say 10A on the 10A circuit and then your compressor kicks in and now you are up to >20A on your 10A circuit which will eventually open the CB.
A 16A CB will usually let you exceed the 16A safely for a few seconds maybe even 10s of seconds, but its still not a good idea to rely on that as it won't let you run the compressor continuously this way anyway.

[Farnx]

Thanks for the reply bob
Yeah that's what i thought it would have to go on a 15A dedicated circuit.
I might get a few more quotes but i have had one sparkie around to take a look.
my shed is about 20 -25m from fuse box.
He was going to run a wire from fuse box through the roof and out through the current conduit in the side of my house which the current wires are feeding the shed. (the previous owners taped into a power point in the house and ran a flexible pipes through the brick)
He quoted me $1000 which Im not sure is good or bad, so i will get a few more quotes.

i have a dedicated 15Amp plug in the fuse box which is used for a caravan.
I guess i could get a 15A extention lead and spray paint in my double garage for now.
Would there be much voltage drop over a 15A lead? surely not enough for the compressor to not run?
cheers

[BobL]

Thanks for the reply bob
Yeah that's what i thought it would have to go on a 15A dedicated circuit.
I might get a few more quotes but i have had one sparkie around to take a look.
my shed is about 20 -25m from fuse box.
He was going to run a wire from fuse box through the roof and out through the current conduit in the side of my house which the current wires are feeding the shed. (the previous owners taped into a power point in the house and ran a flexible pipes through the brick)
He quoted me $1000 which Im not sure is good or bad, so i will get a few more quotes.

i have a dedicated 15Amp plug in the fuse box which is used for a caravan.
I guess i could get a 15A extention lead and spray paint in my double garage for now.
Would there be much voltage drop over a 15A lead? surely not enough for the compressor to not run?
cheers

Yeah , the old "tapping into a 10A house circuit" was they way it was done for a long time"

Using 15A lead
It would probably be OK for intermittent use if a true 2.5mm (not 1.5mm) cable extension cord is used. I wouldn't spray paint like that though