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Technical Dryer Question

B

Bubbles Galore

Active member
I have a current dryer setup using 2-15 HP motors that run from a 3 phase 100 amp breaker. I have the opportunity to purchase 2-10 HP dryers to add to my setup. My question is since I can't expand my electrical capabilities out any further, can my current 100 amp breaker handle this type of addition with a possible delayed start?

Thoughts?
 
If the right type of breaker is in place now, you should have no problem adding 20 more amps to an existing 45 amps on a 100-amp breaker. There should be a breaker in place that won't trip from the high startup load of the motors already; if there's not you can change it to one. You could add the new motors on their own starter with a delay so they don't kick in until the existing ones have spun up.
 
What voltage is your site?

A 15 hp 220 volt three phase motor draws 40 amps. A 10 hp draws 30 amps. That makes 140 amps. PLUS you need to allow 1.25x for startup / service factor.

If you are 208 then your 100 amp breaker will never supply enough power.

If you are 440 volt, then you should be okay. 15 hp, 440 volt motor draws 20 amps, 10 hp draws 15 amps. Thats 70 amps x 1.25 = 88 amps.
 
I have a slide chart from square D and it says a 15 HP motor draws 48.3 Full load amps and should have a circuit breaker of 90 amps @ 208 volts.

For 230 volts it list FLA at 42 amps and calls for a 80 amp breaker.
 
I don't know what I was thinking when I posted above - my brain read "HP" as "amps" so I just added up the horsepower and it was well under 100.
 
What is your limitation in adding a new breaker? How many amps is your incoming main power supply?

How many SS bays do you have? I am pretty sure you have just the one Razor automatic.

Just trying to get an idea of what you have going on there so that I can make a more educated suggestion.
 
Razor Pump Station: 70 Amps
UCC - 40 Amps
Self Serve Bays: 6 x 15 amps = 90 Amps for 5 hp motors
Air Compressor: 15 amps
Vacuums - 60 amps total across 3 phases
That is 275 amps so far at full load.
These numbers are approximate.

Add your whole dryer (50 hp, 140 amp total) and you are just over your 400 amp limit without counting any lighting etc... An electrician should confirm this for you.

My thought is that the only way you could make this work would be to interlock the automatic pump station / auto teller so that the Razor pump station will not kick in while all 4 dryers run. This will have a definite effect on your throughput.

OR maybe just add 1 of the 10 hp motors. No matter what, you will have to bring more power from your main panel.
 
Ask an electrician about adding a sub-panel. I remember we had a customer who balked at adding an IBA because he'd been quoted $15,000 to pull new service after one electrician said his current panel wouldn't handle the addition. It turned out his service was fine (Much less than your 400 amps), he just didn't have enough breakers. A $600 breaker box took care of it.
 
I have an electrician that is going to come out tomorrow and take a look at the site, but I already have a sub-panel off my main panel so I'm thinking I might be out of luck with adding an additional 20 HP...
 
Drying is about efficiency/design not Horsepower as many manufactures want you to believe. Throwing more horsepower at drying will increase your operating expense. We use the Thrust Pro Dryer, it has four 7.5 HP motors. I have a used one if your interested.......
http://youtu.be/LykgahXUHR4
 
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