Motor Nameplate Data Help?

Hello,

I’m having difficulties understanding a data sheet that I have for an Indramat servo motor. I’m working on trying to find some typical ratings that don’t seem to be very straight forward from the motor’s datasheet/nameplate. If you refer to the attached image, I have a few questions:

-Near the top, there is a cooling mode section which (I believe) separates the motor model into 3 sub categories. However, what do the descriptions of Natural 60K and Natural 100K mean? What are these numbers and what is the K represent?

-The characteristic motor speed. I would have expected this to be in RPM, but the units are simply min-1. Does this represent per minutes? What per minute? RPM?

-Right below that, the continuous torque at standstill has values that are provided. But why are there two numbers in a single box? Why is there 12,0? Is the comma meant to represent a decimal point?

I realize this isn’t exactly a PLC question, but the overall project I’m working on is implementing a new PLC which needs to interact with a new motor replacement. Thank you

tomizzo11 said:

Hello,

-Near the top, there is a cooling mode section which (I believe) separates the motor model into 3 sub categories. However, what do the descriptions of Natural 60K and Natural 100K mean? What are these numbers and what is the K represent?

Click to expand...

look to the left it says :
cooling mode > Natural
overtemperature> 60k
60k/100k temperature in kelvins?

tomizzo11 said:

-The characteristic motor speed. I would have expected this to be in RPM, but the units are simply min-1. Does this represent per minutes? What per minute? RPM?

rpm=revolutions per minute, or simply 1/minute or minute-1

Click to expand...

tomizzo11 said:

-Right below that, the continuous torque at standstill has values that are provided. But why are there two numbers in a single box? Why is there 12,0? Is the comma meant to represent a decimal point?

Click to expand...

Yes, comma for decimal point

I can help you with part of it.

tomizzo11 said:

-The characteristic motor speed. I would have expected this to be in RPM, but the units are simply min-1. Does this represent per minutes? What per minute? RPM?

Click to expand...

Mathematically, when something is raised to a negative power its the same as dividing. Its just another way of expressing revolutions divided by minutes. rev/min = rev*min^-1. Its a quite common notation and is really useful when converting between units because all you need to do is sum the exponents instead of worrying about what units cancel out.

-Right below that, the continuous torque at standstill has values that are provided. But why are there two numbers in a single box? Why is there 12,0? Is the comma meant to represent a decimal point?

Click to expand...

Yes, that is twelve point zero (written out for clarity). In most of the world a comma is used as a decimal marker. The UK and US and a couple of other odd balls are the ones that use a period. (You computer actually has a setting for this).

marcius said:

look to the left it says :
cooling mode > Natural
overtemperature> 60k
60k/100k temperature in kelvins?

Click to expand...

Close but...
60 kelvin = -213.15 degree Celsius
100 kelvin = -173.15 degree Celsius

A common way Siemens and others denote synchronous motor specs is to use K values, but they are actually referring to the temperature RISE in kelvins, not an absolute VALUE in kelvins. So what they are saying is that the maximum allowable temperature RISE of the motor insulation over ambient is 60K, which equates to 213.15 degrees C, etc. It's actually a more accurate way of discussing it, because we don't know WHAT the ambient is at the moment, and when (in other specs) we discuss the motor insulation temperature specs in degrees C, people very FREQUENTLY mistake that value to be an absolute value, not a RISE above an unknown value.

jraef said:

Close but...
60 kelvin = -213.15 degree Celsius
100 kelvin = -173.15 degree Celsius

A common way Siemens and others denote synchronous motor specs is to use K values, but they are actually referring to the temperature RISE in kelvins, not an absolute VALUE in kelvins. So what they are saying is that the maximum allowable temperature RISE of the motor insulation over ambient is 60K, which equates to 213.15 degrees C, etc. It's actually a more accurate way of discussing it, because we don't know WHAT the ambient is at the moment, and when (in other specs) we discuss the motor insulation temperature specs in degrees C, people very FREQUENTLY mistake that value to be an absolute value, not a RISE above an unknown value.

Click to expand...

Okay, so it looks like I was correct regarding two of my questions.

Could you explain this concept of over temperature more? The specifications list that acceptable operating temperatures range from 0-40 degrees Celsius. This 60K and 100K over temperature would definitely push that out of range. I’m currently interning and have yet to take a motor theory class so I’m still trying to learn some of the basic motor specifications and their meanings.

Keep in mind all these things were translated from German so, while the wording is linguistically correct, the intent is kind of lost.

Think of the "overtemperature" more in terms of results than as a limit. You have a 60K and a 100K natural column and a 60/100K surface column. In those columns you have torques and currents. What they are saying is if you put the motor in a 40 degree C environment, lock the motor shaft, put the listed current through the motor at standstill, walked away and came back some hours later the motor case temperature would have increased by the column heading temperature. If using the 60 degree K current the final motor temperature will be 100 degrees C (40 degree ambient plus 60 degree rise). If using the 100 degree K current the motor temperature would end up at 140 degrees C. Natural versus surface can be thought of as not fan cooled (natural) and fan cooled (surface). The reason that there is only a single surface cooling current is that the heat is actually generated inside the motor windings and must move through the motor to the case to be radiated. No matter how hard you blow on the case there is a limit to ow much current you can run through the innermost windings before they are damaged.

Keith

tomizzo11 said:

Okay, so it looks like I was correct regarding two of my questions.

Could you explain this concept of over temperature more? The specifications list that acceptable operating temperatures range from 0-40 degrees Celsius. This 60K and 100K over temperature would definitely push that out of range. I’m currently interning and have yet to take a motor theory class so I’m still trying to learn some of the basic motor specifications and their meanings.

Click to expand...

What jraef says makes sense.
Lets say operating temperature 40 degrees celsius temperature raise 100k (or 100 deg Celsius). That gives us max temperature of 140 deg celsius wich is still lower than 155 deg celsius.
Look at your data sheet on one of lines it says: Insulation class F.
For F class insulation motors max operation temperature is 155 degrees celsius.

I appreciate the help you guys. I also stumbled across this article, very informational and will answer any question regarding over temperature. http://www.motorsanddrives.com/cowern/motorterms4.html

tomizzo11 said:

Hello,

I’m having difficulties understanding a data sheet that I have for an Indramat servo motor. I’m working on trying to find some typical ratings that don’t seem to be very straight forward from the motor’s datasheet/nameplate. If you refer to the attached image, I have a few questions:

-Near the top, there is a cooling mode section which (I believe) separates the motor model into 3 sub categories. However, what do the descriptions of Natural 60K and Natural 100K mean? What are these numbers and what is the K represent?

-The characteristic motor speed. I would have expected this to be in RPM, but the units are simply min-1. Does this represent per minutes? What per minute? RPM?

-Right below that, the continuous torque at standstill has values that are provided. But why are there two numbers in a single box? Why is there 12,0? Is the comma meant to represent a decimal point?

I realize this isn’t exactly a PLC question, but the overall project I’m working on is implementing a new PLC which needs to interact with a new motor replacement. Thank you

Click to expand...

OK,
As an Ex-Indramat Engineer, I can decipher this for you.
The Natural 60K is related to a 60K temperature rise from ambient for the operational conditions listed, the 100K natural is the same.
The force cooled 60/100K gives you the ratings for the motor when force cooled for a 60 or 100K temperature rise.
There is no need to convert K to deg C as the increment is identical.

Min-1 is minutes to the power of -1 which means 1/minutes, that is per minute. Revolutions are dimensionless, thus a number of revolutions per minute rpm is simply a "number" min^-1.
I don't know how to do superscripts on the forum.

Germany use a comma to represent a decimal point in such data as this.

I don't get what you are saying with regard to two numbers in one box below the rated speed?
In the rows directly below rated speed you have the rated torque at standstill, in Nm, and the current in A required to deliver this torque.

I have subscribed to this thread so I will get emails if you have any other questions.
HTH