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Triple and Quadruple rated , 9 Leads Motors
- Thread starter zlatkodo
- Start date
If you mean motors rated 208-230/460, the wiring plan is either a series delta or series Y for the high voltage and a 2 parallel delta or 2 parallel Y for the low voltages.
In either the delta or Y motors, there are permanent splices inside the stator which allow the series/parallel reconnection with only 9 leads brought out into the terminal box. The connection scheme is permanently fixed as either delta or Y by these splices. In the case of the delta stator, 3 permanent splices at the corners of the delta (1-12, 2-10, 3-11) brought out into the terminal box as 3 leads. In the Y stator, a permant splice between the 10-11-12 leads with no lead brought out to the terminal box. Unwary electricians may connect a delta motor thinking it is the same as the Y one they are replacing or the other way around. The reconnections do not always follow the same numbering plan between the two types of motors!
I assume the ability to operate at 208 (and presumably at 416 which is not a standard voltage in North America) is a matter of making the motor a bit more capable of rejecting heat or being otherwise more robustly constructed to handle the increased amperage caused by the lower voltage while producing rated power output.
In some cases, operation on 208 volts is only permitted with the service factor at 1.0 vs 1.15 for the full voltage rating. I don't believe IEC motors are rated with service factors. The NEMA motor is permitted to operated within it's service factor amperage (15% above rated amps for example) with the operating temperature higher and life shortened somewhat, but it should not experience immediate failure as a result.
In either the delta or Y motors, there are permanent splices inside the stator which allow the series/parallel reconnection with only 9 leads brought out into the terminal box. The connection scheme is permanently fixed as either delta or Y by these splices. In the case of the delta stator, 3 permanent splices at the corners of the delta (1-12, 2-10, 3-11) brought out into the terminal box as 3 leads. In the Y stator, a permant splice between the 10-11-12 leads with no lead brought out to the terminal box. Unwary electricians may connect a delta motor thinking it is the same as the Y one they are replacing or the other way around. The reconnections do not always follow the same numbering plan between the two types of motors!
I assume the ability to operate at 208 (and presumably at 416 which is not a standard voltage in North America) is a matter of making the motor a bit more capable of rejecting heat or being otherwise more robustly constructed to handle the increased amperage caused by the lower voltage while producing rated power output.
In some cases, operation on 208 volts is only permitted with the service factor at 1.0 vs 1.15 for the full voltage rating. I don't believe IEC motors are rated with service factors. The NEMA motor is permitted to operated within it's service factor amperage (15% above rated amps for example) with the operating temperature higher and life shortened somewhat, but it should not experience immediate failure as a result.
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The standard nine lead NEMA motors are dual voltage whether wye connected internally or delta connected internally.
Some standard voltages in NEMA land are 120:208 V wye and 277:480 volts wye. A typical nine lead motor will be rated for connection at either 230 V or 460 V for use on 240 V and 480 V respectively
Another common voltage is 120:208 Volts wye. 230 Volt motors worked well for many years on 208 Volt systems but times change. With higher efficiency motors and the reduction of tolerances from 15% to 10% more issues were arising with the use of 230 Volt rated motors on 208 Volt systems.
You can consider 200-230/460 Volt or 208-230/460 Volt rated motors as 200 or 208 Volt motors with enough iron that they may be used on 240 Volts systems without saturating.
You may consider them as motors with wider than normal tolerances.
Or, you may consider them as 230 Volt motors that are slightly over rated HP and torque so that they may be used on 200 or 208 Volt systems without problems.
These motors are dual voltage motors with a 2:1 voltage ratio. There may be a little extra extra HP available when they are used on 240 Volt or 480 Volt systems.
I see 200-208/460 Volt rated motors in hermetic refrigeration compressors and 208-230/460 volt ratings in general purpose motors and agricultural motors and also single phase motors.
As an additional anecdote, I am now living in a rural area where the grid voltage is not well regulated. I advocate the use of 208-230/460 Volt single phase motors on 120/240 Volt services as they withstand low voltage conditions much better than standard 230/460 Volt motors.
Bill
--------------------
"Why not the best?"
Jimmy Carter
Some standard voltages in NEMA land are 120:208 V wye and 277:480 volts wye. A typical nine lead motor will be rated for connection at either 230 V or 460 V for use on 240 V and 480 V respectively
Another common voltage is 120:208 Volts wye. 230 Volt motors worked well for many years on 208 Volt systems but times change. With higher efficiency motors and the reduction of tolerances from 15% to 10% more issues were arising with the use of 230 Volt rated motors on 208 Volt systems.
You can consider 200-230/460 Volt or 208-230/460 Volt rated motors as 200 or 208 Volt motors with enough iron that they may be used on 240 Volts systems without saturating.
You may consider them as motors with wider than normal tolerances.
Or, you may consider them as 230 Volt motors that are slightly over rated HP and torque so that they may be used on 200 or 208 Volt systems without problems.
These motors are dual voltage motors with a 2:1 voltage ratio. There may be a little extra extra HP available when they are used on 240 Volt or 480 Volt systems.
I see 200-208/460 Volt rated motors in hermetic refrigeration compressors and 208-230/460 volt ratings in general purpose motors and agricultural motors and also single phase motors.
As an additional anecdote, I am now living in a rural area where the grid voltage is not well regulated. I advocate the use of 208-230/460 Volt single phase motors on 120/240 Volt services as they withstand low voltage conditions much better than standard 230/460 Volt motors.
Bill
--------------------
"Why not the best?"
Jimmy Carter
Are talking triple or quadruple voltage ratings or HP ratings ? Because unless the speed is changed with the connections, I don't see how HP ratings can change.
Muthu
Muthu
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- #6
zlatkodo,
EASA has a technical note on this; 'Tech Note 10: Winding Connections for Multi-Mode Three Phase Motors.' The tech note covers double, triple, and quadruple-rated windings.
The article is a theoretical discussion of this type of winding explained in a basic manner that is easy to understand. There used to be a related EASA article on "Combined Wye-Delta Windings" that is no longer available. Unfortunately, all of this material is copyrighted so I cannot provide you with copies or links.
I will comment that you have posted several questions lately related to electric motor windings. If you are an electric motor rewinder or an engineer who works in the electric motor rewind field (like I am) then I would suggest that you join EASA so that you can benefit from the resources that they offer to their members. This includes access to numerous technical articles like the one I am referring to, books for connection diagrams (you have asked those questions in different posts) and other technical resources. Membership information can be found here:
(( RULES OF POSTING DISCLAIMER: Please note that I am not soliciting membership to this organization. I am merely suggesting to those who work in this field that this membership offers useful benefits. I am also answering the OP's original question of "where can I find this information."))
For a description of these motors, I will say that I have never seen a multi-mode motor before. The article suggests that they are mostly used in oil well applications and there are none in my area.
I will not promise a result, but I may be able to get the factory rewind data for a motor like what is shown in the connection diagram that you provided. If so, we can examine it and discuss this topic further. Give me a few days, maybe Tuesday, to have a result.
EASA has a technical note on this; 'Tech Note 10: Winding Connections for Multi-Mode Three Phase Motors.' The tech note covers double, triple, and quadruple-rated windings.
The article is a theoretical discussion of this type of winding explained in a basic manner that is easy to understand. There used to be a related EASA article on "Combined Wye-Delta Windings" that is no longer available. Unfortunately, all of this material is copyrighted so I cannot provide you with copies or links.
I will comment that you have posted several questions lately related to electric motor windings. If you are an electric motor rewinder or an engineer who works in the electric motor rewind field (like I am) then I would suggest that you join EASA so that you can benefit from the resources that they offer to their members. This includes access to numerous technical articles like the one I am referring to, books for connection diagrams (you have asked those questions in different posts) and other technical resources. Membership information can be found here:
(( RULES OF POSTING DISCLAIMER: Please note that I am not soliciting membership to this organization. I am merely suggesting to those who work in this field that this membership offers useful benefits. I am also answering the OP's original question of "where can I find this information."))
For a description of these motors, I will say that I have never seen a multi-mode motor before. The article suggests that they are mostly used in oil well applications and there are none in my area.
I will not promise a result, but I may be able to get the factory rewind data for a motor like what is shown in the connection diagram that you provided. If so, we can examine it and discuss this topic further. Give me a few days, maybe Tuesday, to have a result.
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