Component installation inside control panel

[overkill94]

For those of you who read/responded to my question about the 420 Volt motor, this is the same client

He installed a new contactor/overload on a DIN rail inside a control panel...on the top wall of the enclosure. Obviously most components are installed at the back wall and sometimes on the bottom/side walls but I don't think I've ever seen anything mounted on the top wall unless it was a button or light that was also passing through the enclosure. Is this a general no-no or would it have to be in the component's installation instructions?

 

[petersonra]

some contactors do not care much about their orientation, others do. you would need to check the instructions to see about this particular contactor.

 

[SceneryDriver]

I work in special effects, so I inevitably end up mounting components in strange places and orientations (that often have to be in motion while they operate). Like petersonra said, it's all dependent on what the component does and what the manufacturer says. Most relays don't care, and even things like PLC's and power supplies are usually fine even if doom and gloom is predicted in the data sheet. Practically, it's warmer at the top of any enclosure, so heat sensitive things should be watched more closely, but industrially rated components are designed to take the heat.


SceneryDriver

 

[Jraef]

All contactors have an orientation instruction that limits the angles off of vertical that you are allowed to use the contactor, it's typically about 22.5 deg. off vertical in any direction without de-rating, which is an IEC spec. Some NEMA starters like A-B and Siemens/Furnas are gravity drop out, which means even less deviation from vertical. Besides the mechanical strains and wear issues because the armature guides become useless, there is also a convection cooling issue because the arc chutes are also air flow chambers to dissipate heat in the contacts. Off vertical too far and it begins to trap that heat. Some will allow horizontal mounting (turned it on it's side) if you de-rate the current and reduce the operating duty cycle, but that is the contactor only. Many electro-mechanical overload relays will be expecting vertical or maybe horizontal orientation as far as heat dissipation too, but they would most likely just nuisance trip if totally inverted.

I do not know of one single brand that would permit total inversion like that (hanging down from the top like a bat if I get your meaning) unless maybe a vacuum contactor, which is an expensive beast just to get willy-nilly mounting. A regular contactor may work for a while, but was not designed to. Relays, sure. Contactors and motor starters, no.

 

[overkill94]

All contactors have an orientation instruction that limits the angles off of vertical that you are allowed to use the contactor, it's typically about 22.5 deg. off vertical in any direction without de-rating, which is an IEC spec. Some NEMA starters like A-B and Siemens/Furnas are gravity drop out, which means even less deviation from vertical. Besides the mechanical strains and wear issues because the armature guides become useless, there is also a convection cooling issue because the arc chutes are also air flow chambers to dissipate heat in the contacts. Off vertical too far and it begins to trap that heat. Some will allow horizontal mounting (turned it on it's side) if you de-rate the current and reduce the operating duty cycle, but that is the contactor only. Many electro-mechanical overload relays will be expecting vertical or maybe horizontal orientation as far as heat dissipation too, but they would most likely just nuisance trip if totally inverted.

I do not know of one single brand that would permit total inversion like that (hanging down from the top like a bat if I get your meaning) unless maybe a vacuum contactor, which is an expensive beast just to get willy-nilly mounting. A regular contactor may work for a while, but was not designed to. Relays, sure. Contactors and motor starters, no.

Perfect, thanks Jraef.

When I did a search for a generic contactor I found an Allen-Bradley instruction sheet that had some sort of angle picture but I wasn't exactly sure what it meant, seems like this is the orientation allowances. Guess I'll put the onus on the client and make them prove that this contactor is allowed to be mounted like that.