Max Current

Easy. Pick up the phone and talk to the coil manufacturer.

Are we done here?

Even easier, read the coil specifications from the catalog or the data sheets that came with the contactors

Tell Norris534!

All our service representatives are currently busy helping other customers. Please stay on the line and someone will be available shortly......

So easy even an eight year can do it:

Tips to Effective Internet Searching - Hannon Library

How about a caveman? Can he do it?

lyn-

In addition to that one there are the following aspects of the task.

The in-rush VA is approximately 10 times greater than the sealed VA.

The second value to be considered is the sealed VA, the amount of volt-amperes required to maintain the energized state of an electromagnetic device. This VA requirement will be 5…10 times less than the inrush VA http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/1497-wp001_-en-p.pdf pg 3.

Also-

http://www.industrial-electronics.com/output_devices_amplifiers_valves_relays_variable-frequency_drives_stepper_motors_servomotors/Ratings_for_Coils.html

Written the Lyndoor way, short!

Good Luck, Old Salt

http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/ap03902008e.pdf

No doubt 110 "VAC" is very important. But, you still have to know only "VA".

why is that?

If they will start all together in the same time take 15*200 VA for voltage drop

and 15*50 VA for ampacity [for information only, as average values].

Even easier for 15 motor starters any salesman from a distributor will obtain it for you.

15 motors starting all at the same time. The peak current draw I'd worry about is not from the fifteen contactor coils turned on at the same time.

That's for sure.

I think OP is in over their head.

4I wouldn't use 24 gauge control voltage wire

Unplug one contactor, the specification must be at the nameplate

Look at the coil as see if it is marked on it.

Check the catalog and/or spec sheet for that model.

Unless they are extreme big coils with an high initial current as it pulls in, set one up with the 110vac and measure the initial current and the running current with a fast clamp-on amp meter. Multiply that by 15. Yes, this is not the most accurate method but the reaction time on the circuit breaker/slow blow fuse you will be putting in series with the 15 coils, as protection, will not react as quickly as the overall time of the surge current. Surge current is quicker than the reaction time of the breaker or a slow blow fuse.

Another method would be to use an Extech Instruments Line Splitter #480172 or any other similar to it (about $10-15) between the power and the coil.

Clamp the meter on the X10 loop and measure the current there. Divide it by 10 and you have all the currents for one coil. Once you have a line splitter you will be using it a lot more for other things!

To do it more accurately than the clamp-on will require a current sensitive coil or the line splitter and an oscilloscope.

Good Luck, Old Salt

Coil inrush and sealed VA data is not going to be on the coil itself, but as was said many times now, you can get that info EASILY from any contactor manufacturer right out of their catalog in the "Technical Data" section. They have to put it there, everyone needs that information to be able to size control power transformers, power supplies etc.

Or I guess I should say, at least any manufacturer that is worth doing business with. Cheap bottom feeder knock-off crap from China, maybe that would be difficult, but hey, you get what you pay for...

Right.The manufacturer-usually-gives-in his product catalogue- the AC [or DC] coil data. See -for instance:

file:///C:/Users/win7/Downloads/TB03300002E%20(1).pdf

Look at the coil (sp a) and see if it is marked on it. Who knows that it is not marked on any coil in the USA, China or other countries? Maybe it is worth a look. Shouldn't take much time to see if it is there.

In reference to #15 and #16: reference paragraph #2 in #15---> Doesn't "Check the catalog and/or spec sheet for that model" from #15 mean the same as "but as was said many times now, you can get that info EASILY from any contactor manufacturer right out of their catalog in the "Technical Data" section" from #16? Isn't the term "Technical Data" the same as "Check the catalog and/or spec sheet for that model"? In this area of the country, and many others, it is the same. Schneider uses the term "characteristics" for their TeSys D contactors. I guess that part of #15 is the same as #16, especially the "MANY TIMES now" part. No, maybe the whole #16 is a paraphrase of #15.

Personally I prefer to use the line splitter, a switch, a short length of wire (maybe), the clamp on amp meter and an oscilloscope with software such as "FREEWAVE3" and a real cheap computer. Advantage is it is recorded as many times as liked and it can be looked at over and over. Fortunately I have a freebie so it is real cheap computer.

Good Luck, Old Salt

Easier yet, hire a licensed electrician

Yup, at least they will know who to phone.

If the OP doesn't know where to get the information, they are really in over their head. Anyone that has installed any type of motor starter or contactor knows to look on the data plate on the starter or the specs in the catalog!

Hire a qualified electrician before you kill yourself or your co-workers!