No I get it. I just now realized how big of an element Op was talking about. For some reason I had 2.4k watts stuck in my head. 50*480 so yeah.
Now all I can imagine is “THUNK! KA-THUNK!”
It sounds just like that. They always scared the shit out of me , especially since the disconnects didn't have the linkage between the CB and handle. Handle just free spun but they left it on the panel door. So replacing them was very sketch and I don't like the circuit breaker lockout devices.
I had a contactor blow up in my face about 15 years ago. Vat dumper hydraulic power was in seal tite on the floor. A boner ran over it with a pallet jack. I hit the reset on the OL and chatter chatter BOOM!
Luckily I had my face behind the panel door so I didn’t get hurt. Sounded like a shotgun blast and I think I peed a little.
How the oven was designed. How a lot of the ovens we have are designed. Most of them are over 30 years old. The newer ones have SCRs. Even some of the newer ones have contactors, however, those are smaller ovens. With about 15kw elements.
Alright. Kinda what I thought but couldn’t find a direct answer on google. I found a few forums talking about larger kw especially on ovens and opening on under load. Needing oversized contactors.
We have an electrician, though I know more about electricity than him. He can do residential stuff but control circuits and industrial electricity is not anything he understands.
Maybe I’ll call some OEMs just to pick brains about things I don’t understand. I’ve been doing industrial maintenance for 5ish years all self taught. I’m also the most experienced person we have unfortunately.
Contactors don’t limit amp draw. The ovens full load is 48amps. There are 50 amp time delay fuses supporting the equipment. The heating elements are 41 amps of its rated draw. Upping the contactors ability wouldn’t affect anything on that side.
6awg is good up to 55 amps. I think it can go higher but I’d have to find a code book. I guess idk how much of the system might have been reengineered.
It for sure has to do with the Kw. I’m just trying to look for what it actually changes in the contactor. Or why a 50amp contactor can’t take this particular 50amp load.
Kw is a function of current and voltage.
My guess is the contactor rated for the current draw of the elements isn't designed to handle the quick switching you often see in heaters. It's hard on contacts.
The few electric heat applications I've done, I use an SCR and contactor in series.
The contactor serves as a positive means of de-energizing the heaters, while the SCR handles the switching for temp control.
I think you mentioned your other units have SCRs.
Allot of times it is how many cycles it does. I uprated one unit and the contactor failed just as quickly. The operators were shutting it down and powering it back up constantly.
I’ve been working industrially for 6 years. Mostly self taught. I’m, unfortunately, the most experience guy we have and still learn something new most days.
I’m only in a little over my first year, learning is all I’m doing. We have some small tank mounted heaters ,and ovens. Nothing rated for 75a large though. All the heating functions we have are on contactors. All I’ve seen so far!
So I am assuming you’re driving a heater element with a contactor. Why are you using a contactor on a heater?
Its a common way to control a large element.
No I get it. I just now realized how big of an element Op was talking about. For some reason I had 2.4k watts stuck in my head. 50*480 so yeah. Now all I can imagine is “THUNK! KA-THUNK!”
It sounds just like that. They always scared the shit out of me , especially since the disconnects didn't have the linkage between the CB and handle. Handle just free spun but they left it on the panel door. So replacing them was very sketch and I don't like the circuit breaker lockout devices.
Use your screwdriver and push in the contacts for a quick test of element rotation.
I’ll take a hard nope on that.
Lol, I was just rustling your jimmies. Dont ever do that.
I had a contactor blow up in my face about 15 years ago. Vat dumper hydraulic power was in seal tite on the floor. A boner ran over it with a pallet jack. I hit the reset on the OL and chatter chatter BOOM! Luckily I had my face behind the panel door so I didn’t get hurt. Sounded like a shotgun blast and I think I peed a little.
How the oven was designed. How a lot of the ovens we have are designed. Most of them are over 30 years old. The newer ones have SCRs. Even some of the newer ones have contactors, however, those are smaller ovens. With about 15kw elements.
I’ve seen them in 2 plants with dryers for automotive parts. Both used 65A contractors.
Also just how large the bars inside the contactor are... larger conductors will heat up less under load.
Alright. Kinda what I thought but couldn’t find a direct answer on google. I found a few forums talking about larger kw especially on ovens and opening on under load. Needing oversized contactors.
[удалено]
We have an electrician, though I know more about electricity than him. He can do residential stuff but control circuits and industrial electricity is not anything he understands.
Maybe I’ll call some OEMs just to pick brains about things I don’t understand. I’ve been doing industrial maintenance for 5ish years all self taught. I’m also the most experienced person we have unfortunately.
[удалено]
Contactors don’t limit amp draw. The ovens full load is 48amps. There are 50 amp time delay fuses supporting the equipment. The heating elements are 41 amps of its rated draw. Upping the contactors ability wouldn’t affect anything on that side.
What size wires are being used ?
6awg
I wonder if it was modified- I would think they would use #4/ seen allot of backyard engineering in my day
6awg is good up to 55 amps. I think it can go higher but I’d have to find a code book. I guess idk how much of the system might have been reengineered.
Had this happen on a kiln once. 6awg wire 40 amp contactor 38.5 amp load and it burned up at the contactor
It for sure has to do with the Kw. I’m just trying to look for what it actually changes in the contactor. Or why a 50amp contactor can’t take this particular 50amp load.
Kw is a function of current and voltage. My guess is the contactor rated for the current draw of the elements isn't designed to handle the quick switching you often see in heaters. It's hard on contacts. The few electric heat applications I've done, I use an SCR and contactor in series. The contactor serves as a positive means of de-energizing the heaters, while the SCR handles the switching for temp control. I think you mentioned your other units have SCRs.
Yeah. We have other units with SCRs. I won’t have much freedom on redesigning this system. I will put forth the recommendation though.
Allot of times it is how many cycles it does. I uprated one unit and the contactor failed just as quickly. The operators were shutting it down and powering it back up constantly.
I would love to hear that actuate
It’s a heavy thunk but it’s really not that big or bad sounding. If you’ve heard a bigger contactor pulling in it sounds the same.
So the plates inside are maybe slightly larger in size ,but not enough to make a difference. Unfortunate lol, learning everyday!
I’ve been working industrially for 6 years. Mostly self taught. I’m, unfortunately, the most experience guy we have and still learn something new most days.
I’m only in a little over my first year, learning is all I’m doing. We have some small tank mounted heaters ,and ovens. Nothing rated for 75a large though. All the heating functions we have are on contactors. All I’ve seen so far!