Panels and Motors

[bonding jumper]

I am designing a boiler room panel that is rated 200A and am planning on running a 25hp motor, 3hp motor 1/2hp and a 1/3hp. Does anybody have an objection to running all these motors from a 200A panel? The currents from these motors when u factor in the three phases, comes to 96A. So I am feeding the panel with a 150A circuit breaker from a main distribution panel. And the 200A is a main lug only.

Another question, do i require disconnect switches for these motors if the boiler room panel is in sight of the motors? In other words, does a circuit breaker in a panel qualify as a disconnecting means?

SIDE NOTE: These motors are part of a boiler system, where there is also a boiler control panel, and it seems that the boiler controls the motors by Thermal Switches, but I am pretty sure, that the boiler room panel will carry the loads for the motors, while the boiler control panel, dosn't see these loads, it just sends a signal to the switches to open/close as the configuration requires. Thanx.

[ July 24, 2003, 09:14 AM: Message edited by: bonding jumper ]

 

[bennie]

Re: Panels and Motors

Where are the motor starters?

 

[bonding jumper]

Re: Panels and Motors

In the boiler control panel.

How do motor starters work? If they are in the boiler control panel, does that mean at startup, that the bcp and the boiler room panel engages and after startup, the boiler control panel disengages and power is supplied soley from the boiler room panel, or
Is all power supplied from the boiler control panel? Startup and regular running.

[ July 24, 2003, 10:03 AM: Message edited by: bonding jumper ]

 

[caj1962]

Re: Panels and Motors

The circuit breakers can be used as means of disconect for a motor. However from what you are describing the BCP is what is located within sight of the motors not the panel. The disconecting means for the controler

B) Motor. A disconnecting means shall be located in sight from the motor location and the driven machinery location. The disconnecting means required in accordance with 430.102(A) shall be permitted to serve as the disconnecting means for the motor if it is located in sight from the motor location and the driven machinery location.

If this is not the case then you would have to install seperate disconects for the motors

As far as a motor starter works it is magic.

 

[bennie]

Re: Panels and Motors

Bonding-jumper: I am a bit surprised by your question considering your profile. Your past reponses to other topics have been good and show a degree of knowledge. You may be over your head on this project. You are smart by knowing your limitations and asking questions.

Boiler units are usually just that, a unit. They are somewhat complex, and extremely hazardous, if not installed properly. The many safety devices must not be compromised. I've seen boiler explosions. The site is like that home in Iraq, after the ten tow missile strikes.

The unit should be a stand alone item. There should only be one feeder to the control panel, from the building system. The manufacturer should spell out the requirement. You should not have to fabricate anything to connect the boiler unit.

[ July 24, 2003, 10:25 AM: Message edited by: bennie ]

 

[bonding jumper]

Re: Panels and Motors

I was asking the question because I was being supplied with two sets of information, the mechanical engineer was asking me to supply him with a panel, with breakers for each motor and a seperate 20A breaker for the boiler control panel. I was also given an electrical drawing for a similar boiler control panel, and that control panel had it like Bennie says, one set of terminals, and the power for the entire system goes through those terminals. The two differents sets of info from the mechanical engineer had me confused, so I came here to ask. Thanks for straighting that out for me.

Bennie, thanks for the compliment, as I am an Electrical Engineer graduated dec 03 and thrown into a consulting office where I am the only Electrical Engineer, and you and this forum are one of my only teachers.

[ July 24, 2003, 11:08 AM: Message edited by: bonding jumper ]

 

[bennie]

Re: Panels and Motors

bonding jumper: I will have to correct you, I can't be the only instructor, on this forum, there is many instructing me.

I have a friend and former associate, who is a non-degree engineer. He performed a lot of the circuit design for the first RCA satellite Telstar. He was also instrumental in the development of the SCR, with International Rectifier Corp.

I asked him "why he didn't get his degree". He told me " the curriculum, and textbooks, for the upper level classes he needed for a degree, were all written by him.

My point is...It was rare that I could teach, or show him anything, but when I did, I was on top of the world.

[ July 24, 2003, 11:43 AM: Message edited by: bennie ]