CR4® - The Engineer's Place for News and Discussion®


Previous in Forum: Vibration Analysis and Location   Next in Forum: EAF Working Point Calculation
Close
Close
Close
18 comments
Active Contributor

Join Date: Apr 2018
Posts: 22

Which Motor is Useful in Lift Mechanism?

05/16/2018 7:22 AM

DC Motors have adjustable varying speed and high starting torque. Therefore these are used in elevators. But Dc motor has following drawbacks like

1. low voltage regulation in DC series motors

2. lower speed regulation

3. It can not be run at zero load conditions

Due to thse drawbacks DC motors are not suitable for lifts. Therefore in lifts 3 phase induction motors are used. It has large starting torque and lower starting current.Also the speed can be smoothly controlled by power electronics drives.

Register to Reply
Pathfinder Tags: dc motor
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 9621
Good Answers: 458
#1

Re: Which motor is useful in lift mechanism ?

05/16/2018 7:34 AM

What's the difference between an elevator and a lift?

__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting ["brexit" - ugh] as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 27490
Good Answers: 732
#2
In reply to #1

Re: Which motor is useful in lift mechanism ?

05/16/2018 8:29 AM

The Atlantic Ocean.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 9621
Good Answers: 458
#4
In reply to #2

Re: Which motor is useful in lift mechanism ?

05/16/2018 8:55 AM

Yeabut how come DC motors are suitable for elevators but not for lifts? Guess it's some Ramakrishnan weird.

__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting ["brexit" - ugh] as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 27490
Good Answers: 732
#7
In reply to #4

Re: Which motor is useful in lift mechanism ?

05/16/2018 1:09 PM

CR4 doesn't have a Good Question voting button.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Oct 2008
Posts: 41238
Good Answers: 1618
#5
In reply to #1

Re: Which motor is useful in lift mechanism ?

05/16/2018 10:01 AM

Lifts raise and lower petrol and lorries.

Elevators raise and lower gasoline and trucks.

Register to Reply
Guru
Hobbies - DIY Welding - Wannabeabettawelda

Join Date: May 2007
Location: Annapolis, Maryland
Posts: 4579
Good Answers: 263
#6
In reply to #5

Re: Which motor is useful in lift mechanism ?

05/16/2018 10:42 AM

. . . and store grain.

Register to Reply
Guru
United States - Member - New Member Engineering Fields - Power Engineering - New Member

Join Date: Sep 2006
Location: California, USA, where the Godless live next door to God.
Posts: 4493
Good Answers: 756
#8
In reply to #1

Re: Which motor is useful in lift mechanism ?

05/16/2018 7:30 PM

I believe the semantic difference is that "elevators" move people and are subject to much MUCH more stringent requirements with regard to safety and reliability. The term "lift" is more often associated with things like car parking lifts and freight elevators. Yes, I realize I used one term to define the other, but that's just my observation from when I was involved in equipment for the passenger elevator industry.

That said, MANY of the major players in the passenger elevator industry have embarked on using VFDs and induction motors to replace old DC motors now. It's not something that VFD mfrs pursue directly because of liability concerns (here in the US anyway), but they will sell the VFDs to elevator mfrs who take on that risk.

__________________
** All I every really wanted to be, was... A LUMBERJACK!.**
Register to Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 9621
Good Answers: 458
#10
In reply to #8

Re: Which motor is useful in lift mechanism ?

05/17/2018 4:42 AM

In the UK, the term "lift" is used almost exclusively in either case; if anything, the opposite use of the terms is applied in the applications you describe.

The OP does not reveal their provenance.

__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply
Guru
Engineering Fields - Power Engineering - New Member

Join Date: May 2007
Location: NYC metropolitan area.
Posts: 3231
Good Answers: 445
#3

Re: Which motor is useful in lift mechanism ?

05/16/2018 8:52 AM

Actually, with today's modern electronics and microprocessor control systems, the differences between AC and DC motors is rapidly fading. They are both electromechanical energy conversion devices, and their distinction electrically, ends at the supply terminals.

__________________
“Tell me and I forget. Teach me and I remember. Involve me and I learn.” Ben Franklin.
Register to Reply Score 1 for Good Answer
Guru

Join Date: Oct 2009
Location: sometimes Wales,UK.. was Libya, now Oman!
Posts: 1682
Good Answers: 115
#9

Re: Which Motor is Useful in Lift Mechanism?

05/16/2018 10:27 PM

and your question is?

__________________
The square root of nothing is what you make it!
Register to Reply
Guru

Join Date: Jul 2006
Location: CA (Central Arkansas, USA)
Posts: 570
Good Answers: 9
#14
In reply to #9

Re: Which Motor is Useful in Lift Mechanism?

05/17/2018 1:01 PM

I was wondering if I missed something. I don't remember seeing a question or question mark, either. -- JHF

__________________
If it's too good to be true, it probably isn't
Register to Reply
Guru

Join Date: May 2016
Posts: 1297
Good Answers: 60
#15
In reply to #14

Re: Which Motor is Useful in Lift Mechanism?

05/17/2018 1:44 PM

It's in the title of the thread.

Register to Reply
Guru

Join Date: Jul 2006
Location: CA (Central Arkansas, USA)
Posts: 570
Good Answers: 9
#16
In reply to #15

Re: Which Motor is Useful in Lift Mechanism?

05/17/2018 3:53 PM

AH! So it is. He (she) then proceeded to answer his(her) own question?. -- JHF

__________________
If it's too good to be true, it probably isn't
Register to Reply
Guru

Join Date: Oct 2009
Location: sometimes Wales,UK.. was Libya, now Oman!
Posts: 1682
Good Answers: 115
#17
In reply to #15

Re: Which Motor is Useful in Lift Mechanism?

05/18/2018 1:21 AM

so it is!! The title is a question

The rest is a statement TELLING us what I should be, why it should be and to my mind show all of CR4 how right you are.

Now if you are convinced that you got it right, why post?

__________________
The square root of nothing is what you make it!
Register to Reply
Guru

Join Date: May 2016
Posts: 1297
Good Answers: 60
#18
In reply to #17

Re: Which Motor is Useful in Lift Mechanism?

05/18/2018 11:11 AM

I think the OP was telling what he understood about DC vs induction motors, but wanted confirmation and any other additional alternatives anyone else might have. I had done some elevator code reviews for permitting in the past and know that not only are there many acceptable ways to skin the cat, but also milk the rodent.

Register to Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 12934
Good Answers: 804
#11

Re: Which Motor is Useful in Lift Mechanism?

05/17/2018 7:54 AM

None of your drawbacks are real. There are low voltage and high voltage DC motors. Speed regulation changes with application and motor/drive selection. There is no such thing as a zero load condition. Bearing friction and rotor inertia are not zero.

__________________
"Don't disturb my circles." translation of Archimedes last words
Register to Reply
Power-User

Join Date: Apr 2017
Location: Southern Illinois
Posts: 350
Good Answers: 8
#12

Re: Which Motor is Useful in Lift Mechanism?

05/17/2018 9:09 AM

There are two basic types of DC motors: Series and Shunt. Series has a high torque and Shunt has good voltage/speed regulation. A Compound motor blends different degrees of each type into the same motor. You could even have a separate adjustable field for motor control. There's not much difference between some DC motors and a DC generator. I'm sure someone somewhere can even make a custom motor if there's enough demand for it.

__________________
Science is the "cookbook" for making things.
Register to Reply
Guru

Join Date: May 2016
Posts: 1297
Good Answers: 60
#13

Re: Which Motor is Useful in Lift Mechanism?

05/17/2018 10:59 AM

Any motor could be used in an elevator or lift application. Due to normal friction in the mechanism, a DC series motor would still be working with a load against it and speed control electronics with feedback loop could provide adjusted voltage, up to and including controlled braking by reversed low voltage. Given the state of controls, I would expect to see a rise in the use of brushless DC or servo type motors in the future.

The difference between motor types is getting pretty thin in some areas, such as synchronous vs brushless DC vs 3 phase. The motor configuration is very similar with the main difference being in the control circuitry and the overcapacity built into the motor to allow under-voltage operation or the capability to be used as a torque motor to apply braking, where the direction of torque can be opposite to the direction of actual rotation.

Any motor/control configuration will still have to go through the necessary testing and certification for applicable local, national and international codes and to obtain local permitting and insurance company acceptance, but it can be done if there is enough benefit to justify the expense.

Register to Reply
Register to Reply 18 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Brave Sir Robin (1); brich (2); Circuit Breaker (2); Dennis R. Levesque (1); JohnDG (3); Jpfalt (3); JRaef (1); lyn (1); PWSlack (2); RAMConsult (1); redfred (1)

Previous in Forum: Vibration Analysis and Location   Next in Forum: EAF Working Point Calculation

Advertisement