How do you know when you need a motor starter and when you don't? For example, I am working with (2) 480V/3p/1.5hp belt drive fans. I believe the fans come with thermal overload protection so I was planning on putting them both on the same circuit with a 15A breaker?? How do I know when and what kind of motor starter to use?
Motor Starters
- Thread starter lizzie14
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- Wisconsin
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- PE (Retired) - Power Systems
Re: Motor Starters
The equipment manufacturer should have the information you need.
How are you going to start and stop these motors?
Rarely are 1.5HP motors supplied with integral protection, so I would plan on providing my own. If they all run at the same time I would use a single magnetic contactor (for on-off) feeding individual "manual motor controllers" (i.e. Square D type GV). If they run individually then use motor starters.
see 430.53(C)and 430.109(6)
The equipment manufacturer should have the information you need.
How are you going to start and stop these motors?
Rarely are 1.5HP motors supplied with integral protection, so I would plan on providing my own. If they all run at the same time I would use a single magnetic contactor (for on-off) feeding individual "manual motor controllers" (i.e. Square D type GV). If they run individually then use motor starters.
see 430.53(C)and 430.109(6)
Re: Motor Starters
All motor's need a starter, may just be a switch on the wall, that can be called a starter (or controller), It's just a manual starter. All depends on what you want to do with them. They all also need a disconnecting means, can just be a cord and plug. What you need to figure out is size of starter from what you show you could use a size 0, I personally prefer to not go below a size 1. Then you need to size your overloads and that depends of FLA 430.110. You have to decide if you want both fans on same disconnect 430.112. NEMA starter size for HP ratings is not in the NEC I don't think. Somebody on here will definitely correct me if I'm wrong. But there is a chart available usually in the catalog you order from.
All motor's need a starter, may just be a switch on the wall, that can be called a starter (or controller), It's just a manual starter. All depends on what you want to do with them. They all also need a disconnecting means, can just be a cord and plug. What you need to figure out is size of starter from what you show you could use a size 0, I personally prefer to not go below a size 1. Then you need to size your overloads and that depends of FLA 430.110. You have to decide if you want both fans on same disconnect 430.112. NEMA starter size for HP ratings is not in the NEC I don't think. Somebody on here will definitely correct me if I'm wrong. But there is a chart available usually in the catalog you order from.
petersonra
Senior Member
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- Northern illinois
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- Semi-retired engineer
Re: Motor Starters
why would it need a nema starter in the first place? a $20 iec starter will work fine.
why would it need a nema starter in the first place? a $20 iec starter will work fine.
Re: Motor Starters
Just up to you to decide. Cost's any type of control's, automatic starts, just somebody going to turn it on or off. Sometimes you just need to make a decision. Once you decide there is all the guidance on how to connect it up and size the equipment. I personally have not problem if it were just fans that will probably run almost all the time anyway, put them on a manual starter and be done. Do you want to worry about energy concerns though if it's running and nobody there and they forgot to turn it off? You just have to figure out what you want to do.
By the way, they also make just a straight switch that can start a 3 phase 480 volt motor and you can put overloads in it. Personally I don't like those, would prefer the small push button manual starter.
[ May 12, 2005, 05:37 PM: Message edited by: 69boss302 ]
Just up to you to decide. Cost's any type of control's, automatic starts, just somebody going to turn it on or off. Sometimes you just need to make a decision. Once you decide there is all the guidance on how to connect it up and size the equipment. I personally have not problem if it were just fans that will probably run almost all the time anyway, put them on a manual starter and be done. Do you want to worry about energy concerns though if it's running and nobody there and they forgot to turn it off? You just have to figure out what you want to do.
By the way, they also make just a straight switch that can start a 3 phase 480 volt motor and you can put overloads in it. Personally I don't like those, would prefer the small push button manual starter.
[ May 12, 2005, 05:37 PM: Message edited by: 69boss302 ]
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: Motor Starters
It is strictly the designer's choice.
A starter is simply a combination of a motor controller (430 part VII) and an overload protective device (430 part III). The motor controller can be magnetic (allows remote or automatic control) or manual. The overload device can be properly sized fuses but more typically is a dedicated overload relay.
Personally, I am not a believer in always blindly sizing motor starters as being a minimum of a NEMA Size 1. In this case the motor has an NEC FLC of 3A and a Size 1 starter is rated for 27A, talk about overkill.
It is strictly the designer's choice.
A starter is simply a combination of a motor controller (430 part VII) and an overload protective device (430 part III). The motor controller can be magnetic (allows remote or automatic control) or manual. The overload device can be properly sized fuses but more typically is a dedicated overload relay.
Personally, I am not a believer in always blindly sizing motor starters as being a minimum of a NEMA Size 1. In this case the motor has an NEC FLC of 3A and a Size 1 starter is rated for 27A, talk about overkill.
Re: Motor Starters
petersonra; there are some "people" I will use that term, perhaps more polite and the moderators won't blank out my post. That are staunchly against IEC. I would believe if you chose magnetic starter in this case IEC would be perfect.
Also sorry Jim, that is still a thing that some "people" used to force on the electricians in the steel industry. Just the same as "No conduit smaller than 3/4" or no wire smaller that #12 anywhere aloud in the plant. Money flows freely for some I suppose.
Edit: should read these things over before I post them.
[ May 12, 2005, 05:55 PM: Message edited by: 69boss302 ]
petersonra; there are some "people" I will use that term, perhaps more polite and the moderators won't blank out my post. That are staunchly against IEC. I would believe if you chose magnetic starter in this case IEC would be perfect.
Also sorry Jim, that is still a thing that some "people" used to force on the electricians in the steel industry. Just the same as "No conduit smaller than 3/4" or no wire smaller that #12 anywhere aloud in the plant. Money flows freely for some I suppose.
Edit: should read these things over before I post them.
[ May 12, 2005, 05:55 PM: Message edited by: 69boss302 ]
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: Motor Starters
Actually, there are many valid reasons for minimum sizes of products especially for continuous process industries. The ability to quickley change out any starter (or wire) without having to worry about physical sizes is not always a trivial matter when down time is measured in $000s/minute. My point is that there should be a reason.
Actually, there are many valid reasons for minimum sizes of products especially for continuous process industries. The ability to quickley change out any starter (or wire) without having to worry about physical sizes is not always a trivial matter when down time is measured in $000s/minute. My point is that there should be a reason.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
Re: Motor Starters
There are good reasons to use #12 a s a minimum wire size too. It's far less likely to be damaged in pulling.
There are good reasons to use #12 a s a minimum wire size too. It's far less likely to be damaged in pulling.
tony_psuee
Senior Member
- Location
- PA/MD
Re: Motor Starters
I would confirm with the manufacturer that the motors have the overloads. We use 1.5hp fractional motors, 56 frame, that have internal thermal overloads. When we move to a 1.5hp integral motor then we need to supply the thermal overload.
Tony
I would confirm with the manufacturer that the motors have the overloads. We use 1.5hp fractional motors, 56 frame, that have internal thermal overloads. When we move to a 1.5hp integral motor then we need to supply the thermal overload.
Tony
Re: Motor Starters
You make sense for those arguments jim and peter but what about when your putting together a small panel and even the connectors on the control relays that said "people" specked out without realizing that the control relay connector wont accept anything over an 18 gauge wire but your not allowed to use anything less than 12 so same said person has you cut down the strands so that it will fit.
Where it sets up a good practice for pulling wire it sets a bad practice and president for the guys to later decide oh it must be OK to just trim off a few strands off this MCM 500, we do it all the time.
Standards are OK but we as managers should use our heads and apply standards correctly instead of just to maintain a standard we establish an unsafe work practice.
Sorry I let myself start rambling.
You make sense for those arguments jim and peter but what about when your putting together a small panel and even the connectors on the control relays that said "people" specked out without realizing that the control relay connector wont accept anything over an 18 gauge wire but your not allowed to use anything less than 12 so same said person has you cut down the strands so that it will fit.
Where it sets up a good practice for pulling wire it sets a bad practice and president for the guys to later decide oh it must be OK to just trim off a few strands off this MCM 500, we do it all the time.
Standards are OK but we as managers should use our heads and apply standards correctly instead of just to maintain a standard we establish an unsafe work practice.
Sorry I let myself start rambling.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: Motor Starters
69boss302,
My preference is to chose the correct device for the application. To chose device you need to consider the duty cyle, service factor, and especially the attitude of the customer. NEMA sizing was created to reduce the number of options not to ensure a level of performance.
When given the chance, I specify IEC rated (and UL Listed) devices.
69boss302,
My preference is to chose the correct device for the application. To chose device you need to consider the duty cyle, service factor, and especially the attitude of the customer. NEMA sizing was created to reduce the number of options not to ensure a level of performance.
When given the chance, I specify IEC rated (and UL Listed) devices.
Re: Motor Starters
I am really glad to hear that Jim, hope you didn't take any of what I have said personally. I have just been exposed to to?many of the idiots that think there is only one way to do something and it's their way and since it's their way it is correct, doesn't matter what any one or any standard say's. I'll calm down from all this some day, but I think I'm starting to actually enjoy being mad at said "people"
(NO nobody on here, just old memories). I have seen alot of people on here that have had to deal with the same situations. Heck I'm still working on learning this dang NEC.
Edit: Also lizzie14 I apologize, welcome to the forum you could probably say that you've been officially threadnaped
[ May 13, 2005, 03:09 PM: Message edited by: 69boss302 ]
I am really glad to hear that Jim, hope you didn't take any of what I have said personally. I have just been exposed to to?many of the idiots that think there is only one way to do something and it's their way and since it's their way it is correct, doesn't matter what any one or any standard say's. I'll calm down from all this some day, but I think I'm starting to actually enjoy being mad at said "people"
(NO nobody on here, just old memories). I have seen alot of people on here that have had to deal with the same situations. Heck I'm still working on learning this dang NEC.Edit: Also lizzie14 I apologize, welcome to the forum you could probably say that you've been officially threadnaped
[ May 13, 2005, 03:09 PM: Message edited by: 69boss302 ]
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
Re: Motor Starters
I also mentioned PULLING wires. I don't have a problem with requiring wires that have to be pulled to be #12. They are far less likely to be damaged than #14. Wires inside a small control panel are not being yanked through conduit.
But, if you indeed used a device that had terminations that would not accept a #12, than obviously you would need to make some kind of accommodation for that if the wire had to be pulled. An obvious (and common) solution is to terminate the pulled #12 at a terminal block, and than run smaller wire to the device.
I have never run across such a relay socket. All I have seen will accept at least a #14.
I also mentioned PULLING wires. I don't have a problem with requiring wires that have to be pulled to be #12. They are far less likely to be damaged than #14. Wires inside a small control panel are not being yanked through conduit.
But, if you indeed used a device that had terminations that would not accept a #12, than obviously you would need to make some kind of accommodation for that if the wire had to be pulled. An obvious (and common) solution is to terminate the pulled #12 at a terminal block, and than run smaller wire to the device.
Re: Motor Starters
As I said, I'm just venting. This guy just had these relay's I don't even know where he got them. Similar to ice cube relays, we were told to use them, they had screw connectors sticking out and they did not fit anything bigger than 18. So the actual listing was probably smaller.
We tried suggesting the terminal strips solution you mentioned, but "why spend the extra money".
He really got upset when I said, why spend the extra money on 12 wire when you could use 18. It was all within the panel. Because I agree with 12's for pulling wire reasons. I've had the 14's break before. What a hassle.
As I said, I'm just venting. This guy just had these relay's I don't even know where he got them. Similar to ice cube relays, we were told to use them, they had screw connectors sticking out and they did not fit anything bigger than 18. So the actual listing was probably smaller.
We tried suggesting the terminal strips solution you mentioned, but "why spend the extra money".
He really got upset when I said, why spend the extra money on 12 wire when you could use 18. It was all within the panel. Because I agree with 12's for pulling wire reasons. I've had the 14's break before. What a hassle.
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