My new oven!

J

jaxxas

Well-Known Member
So just to share I got my new oven today, an Evenheat kf225 TAP. Pretty nice I think. I went with the 22.5" cause I'd rather be too big than too small and I don't really see myself making anything bigger than a machete.




Over all....



Tap controller......



Model......



Plug...



My wall outlet....


The plug which is a 240 volt single phase 15 amp plug is giving me a bit of a problem. I had hoped I could just adapt it over to my current outlets but it doesn't look like that is possible. If anybody has any advice to share about how to do this I'm all ears.


Otherwise I'll probably call my friendly neighborhood electrician, I could use yet another 240 V outlet in addition to the one for the oven.


TIA!
 
The literature and Evenheat Rep. says to use a 240V/20A, NEMA 6-R plug and outlet configuration. It's easy to change out yourself, but I would get an electrician if you have no experience working with electrical wiring. NEMA 6-R is the designation for how the prongs are arranged on the power cord and the female outlet.

The easiest thing to do is just call Evenheat and talk to customer service, they can tell you what you need. I prewired my shop with 220V and the Evenheat Rep said that the oven will work on 220V if you don't already have 240V. Be sure to confirm with them that 220V will not null and void your warranty. If anything, the 220V may not allow the oven to reach it's optimum operating parameters.

Good luck

Grizzly Bear
 
Thanks guys for the input!

So I now understand that this new fangled plug is still just two 110 volt legs and a ground. I can make the adapter!

But now I'm getting greedy!
wink.gif



So my circuit in question is a 30amp 220v dryer circuit. (currently unused)

The new oven pulls 15 amps at 220v.

My new soon to be arriving grinder has the following motor installed

http://www.leeson.com/leeson/searchp...&productType=0

and it pulls 6.2 amps at 220 v, (this is a 3 phase motor powered through a VFD)

so between the 2 'appliances' I am using ~22 amps,

I'm thinking I can run both appliances off the same circuit, I think the 80% rule applies here? So I shouldn't run more a total of 24 amps on this 30 amp circuit? I'm guessing I'm good to go? Please any smart electrical guys check my sanity!?

TIA!

BTW I have gas heat, a gas dryer, gas hot water and a gas kitchen stove. My only normal large electrical draw is the air conditioning. Also the house was wired to be all electric, so I have plenty of untapped power available, just interested in doing so safely!
 
You need to take account of the starting current drawn by the motor.

I'm in Europe, so I'm not familiar with the vagaries of US code and can only talk in very general terms, but I think you should be OK running through the VFD.

Over here, most breakers on domestic circuits are type B. They will trip instantly if the current drawn is about 3 times the nominal current. For circuits with motors, the norm is to use type C breaker instead, which will trip instantly when the current drawn is about 5 times the nominal current.

A motor will usually draw several times its nominal running current during startup, whether single-phase or 3-phase. Across-the-line starting of a 3-phase motor usually draws about 6 times the rated current for a short period. I'm not sure what the factor is for a single-phase motor, but it'll be "several".

Running with any VFD I've ever used, you can program a slow ramp-up to keep the motor starting current right down and if you do this, you'll be fine. I usually go for 10 seconds to maximum speed.

That 6.2 Amps is the amps per phase on the 3-phases to the motor. The current drawn by the VFD will be higher. You need to check the spec on the VFD, rather than the motor, to make sure you are still within limits for your supply. I vaguely recall the factor for a 3-phase motor as being 1.73 (square root of 3), so a perfectly efficient VFD would draw about 11 Amps and your real VFD will draw more.
 
timgunn said:
You need to take account of the starting current drawn by the motor.

I'm in Europe, so I'm not familiar with the vagaries of US code and can only talk in very general terms, but I think you should be OK running through the VFD.

Over here, most breakers on domestic circuits are type B. They will trip instantly if the current drawn is about 3 times the nominal current. For circuits with motors, the norm is to use type C breaker instead, which will trip instantly when the current drawn is about 5 times the nominal current.

A motor will usually draw several times its nominal running current during startup, whether single-phase or 3-phase. Across-the-line starting of a 3-phase motor usually draws about 6 times the rated current for a short period. I'm not sure what the factor is for a single-phase motor, but it'll be "several".

Running with any VFD I've ever used, you can program a slow ramp-up to keep the motor starting current right down and if you do this, you'll be fine. I usually go for 10 seconds to maximum speed.

That 6.2 Amps is the amps per phase on the 3-phases to the motor. The current drawn by the VFD will be higher. You need to check the spec on the VFD, rather than the motor, to make sure you are still within limits for your supply. I vaguely recall the factor for a 3-phase motor as being 1.73 (square root of 3), so a perfectly efficient VFD would draw about 11 Amps and your real VFD will draw more.
Click to expand...
+


Thanks Tim,

I'm fairly ignorant of exactly how VFD's operate!

I looked it up, and it looks as though it only pulls about 9 amps if I'm reading this right.

http://www.kbelectronics.com/data_sheets/kbda.pdf

On the other hand I'm past my greedy stage, I think I'm better off (safer) using 1 circuit per machine. So I will be calling up my electrician.
 
what Tim is explaining is important. The label on the motor and on the VFD shows "Full Load Amps" even if it only says "Amps".

Full load amps is the current draw when the device is running. However, when you first turn on a motor it draws up to 5 or 6 times that much current for a very short time. This is called "in-rush" current. This is because a motor is a big electromagnet. It requires electric current to charge the windings and create the magnetic field. Since the rotor is not turning, it takes a relatively high amount of starting torque to get the shaft spinning. All of this results in high current. As the speed of the shaft comes up the current draw drops off to the normal amp draw.

Tim also explained that you can limit this inrush current. Your VFD has various setting. One of these is the "ramp UP" or "acceleration" time. By setting the VFD to come up to speed over several seconds instead of instantly, the amp draw will be a lot less during startup.

The motor can't draw amps that the VFD won't give, so the VFD sees these amps as well. Therefore the circuit breaker feeding the VFD sees the same amps. Limiting the amps on startup will be a lot easier on your circuit breaker.


Sent from my iPhone using Tapatalk
 
Last edited:
John Wilson said:
what Tim is explaining is important. The label on the motor and on the VFD shows "Full Load Amps" even if it only says "Amps".

Full load amps is the current draw when the device is running. However, when you first turn on a motor it draws up to 5 or 6 times that much current for a very short time. This is called "in-rush" current. This is because a motor is a big electromagnet. It requires electric current to charge the windings and create the magnetic field. Since the rotor is not turning, it takes a relatively high amount of starting torque to get the shaft spinning. All of this results in high current. As the speed of the shaft comes up the current draw drops off to the normal amp draw.

Tim also explained that you can limit this inrush current. Your VFD has various setting. One of these is the "ramp UP" or "acceleration" time. By setting the VFD to come up to speed over several seconds instead of instantly, the amp draw will be a lot less during startup.

The motor can't draw amps that the VFD won't give, so the VFD sees these amps as well. Therefore the circuit breaker feeding the VFD sees the same amps. Limiting the amps on startup will be a lot easier on your circuit breaker.


Sent from my iPhone using Tapatalk
Click to expand...


Thanks John,

I did understand that it was important, important information that I hadn't already considered. I downloaded the manuals and read up on it, and will probably go over it again at least a couple times before actually using the grinder. I understand the ability to program the 'ramp up' time to mitigate the amp draw and plan to do so per Tim's suggestion at least initially. I guess maybe I didn't give Tim due acknowledgement, but thanks again Tim, it is good info and I will put it to use!
 
if you are using a 30 amp breaker, you have more than enough power to run both machines, you just need two outlets. a good VFD will allow you to accelerate slowly so you are never pulling max amps.
 
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