# Swinburne’s Test for DC Machines

In this technique, the DC Generator or DC Motor is run as a motor at no load; with that losses of the DC machines are determined. When the losses of DC machine well-known, then we can find the efficiency of a DC machine in advance at any desired load. In DC machines this test is applicable only throughout the flux is constant at all load (DC Shunt machine and DC Compound Machine). This test maintains of two steps;

### Determination of Hot Resistance of Windings:

The resistance of armature windings and shunt field windings are measured with the help of a battery, ammeter and voltmeter. Since these armature and shunt filed resistances are measured while the DC machine is cold, it should be transformed to values equivalent to the temperature at which the DC machine would work at full load. These values are measured generally when the room temperature increases above 40oC. Take on the hot resistance of armature winding and shunt field winding be Ra and Rsh correspondingly.

### Determination of Constant Losses:

On no load the DC machine run as a motor with the supply voltage is varied to the normal rated voltage. With the use of the field regulator R the motor speed is varied to run the rated speed which is shown in the figure.
Let
V = Supply Voltage
Ish = Shunt Field current ready by A2
No load armature current Iao = I0 – Ish
No load Input power to motor = VI0
No load Input power to motor = VIa0
= V (I0 – Ish)

As the output power is nil, the no loads input power to the armature provides Iron loss, armature copper loss, friction loss and windage loss.

Constant loss Wc = Input power to Motor – Armature copper loss
Wc = VI0 – (I0 – Ish2Ra)

As the constant losses are identified, the efficiency of the DC machine at any loads can be determined. Suppose it is desired to determine the DC machine efficiency at no load current. Then,
Armature current Ia = I-Ish (For Motoring)
Ia = I+Ish (For Generating)

#### To find the Efficiency when running as a motor:

Input power to motor = VI
Armature copper loss =Ia2Ra = (I-Ish2Ra)
Constant Loss = Wc
Total Loss = (I-Ish2Ra)+Wc
Motor Efficiency η = (Input power – Losses)/ Input
η = {VI – (I-Ish2Ra)} / VI

#### To find the Efficiency when running as a Generator:

Output Power of Generator = VI
Armature copper loss =Ia2Ra = (I+Ish2Ra)
Constant Loss = Wc
Total Loss = (I+Ish2Ra)+Wc
Motor Efficiency η= Output power/ (Output power + Losses)
η  = VI / {VI + (I+Ish2Ra) + Wc}

#### Merits:

• Since this test is no load test, power required is less. Hence the cost is economic.
• The efficiency of the machine can be found very easily, because the constant losses are well known.
• This test is appropriate.

#### Demerits:

• When the DC machine is loaded, this test does not deliberate the stray load loss that occurs.
• Using this method we cannot check the DC machine performances at full load.
Example: It does not indicate the commutation performance is satisfactory on full load and cannot indicate the specified limit of temperature rise.
• Using this test we cannot determine the accurate efficiency of DC machine, because iron loss at actual loads is greater than at no load. This is primarily owed to armature reaction interfere with field.

#### Read Comment Policy We have Zero Tolerance to Spam. Chessy Comments and Comments with Links will be deleted immediately upon our review.

1. Hi, Please Send me Template , Thanks
[Superbests9835@gmail.com]

1. You need to pay \$69. If interested let me know. Then i will send the link from where to purchase.

3. never you will get

4. Hi....
First I sorry, I am doing comment not on behalf of this post...
I am gonna to buy this template, before buying this In would like to know experience on the same.. specially on SEO part...

6. Superior post, keep up with this exceptional work. It's nice to know that this topic is being also covered on this web site so cheers for taking the time to discuss this! Thanks again and again! irf540 replacement

7. Hi there! Nice post! Please tell us when I will see a follow up! 토토커뮤니티

8. Thanks for the blog filled with so many information. Stopping by your blog helped me to get what I was looking for. Now my task has become as easy as ABC. source

9. Great job for publishing such a beneficial web site. Your web log isn’t only useful but it is additionally really creative too. 릴게임

10. I have read your article couple of times because your views are on my own for the most part. It is great content for every reader. 안전놀이터

11. Impressive web site, Distinguished feedback that I can tackle. Im moving forward and may apply to my current job as a pet sitter, which is very enjoyable, but I need to additional expand. Regards. 토토커뮤니티

12. Im no expert, but I believe you just made an excellent point. You certainly fully understand what youre speaking about, and I can truly get behind that. 88카

13. Hi there! Nice stuff, do keep me posted when you post again something like this! 안전놀이터

14. Nice knowledge gaining article. This post is really the best on this valuable topic. 파워볼게임

15. You there, this is really good post here. Thanks for taking the time to post such valuable information. Quality content is what always gets the visitors coming. 대전1인샵

16. Thank you so much for the post you do. I like your post and all you share with us is up to date and quite informative, i would like to bookmark the page so i can come here again to read you, as you have done a wonderful job. nursing test bank

17. Good morning!! I am also blogging with you. In my blog,
articles related to are mainly written, and they are usually
(mm)

18. Pretty good post. I have just stumbled upon your blog and enjoyed reading your blog posts very much. I am looking for new posts to get more precious info. Big thanks for the useful info. 현금바둑이

19. Thanks for another wonderful post. Where else could anybody get that type of info in such an ideal way of writing? 먹튀폴리스

20. Someone Sometimes with visits your blog regularly and recommended it in my experience to read as well. The way of writing is excellent and also the content is top-notch. Thanks for that insight you provide the readers! 먹튀검증

21. This is such a great resource that you are providing and you give it away for free. I love seeing blog that understand the value of providing a quality resource for free. 먹튀검증

22. This is a good post. This post gives truly quality information. I’m definitely going to look into it. Really very useful tips are provided here. Thank you so much. Keep up the good works. 먹튀검증

23. This is my first time visit here. From the tons of comments on your articles,I guess I am not only one having all the enjoyment right here! 온라인바둑이

24. 바카라사이트
Hello I am so delighted I located your blog, This is my website and it has been very helpful. That's a cool article. Thanks for the analysis presented here. I am still illiterate on this subject. So this post has been very helpful for me personally. I think a few things I learned from your post will give me the support I personally need. thank you!

25. Superior post, keep up with this exceptional work. It's nice to know that this topic is being also covered on this web site so cheers for taking the time to discuss this! Thanks again and again! 꽁머니 1만

27. I definitely enjoying every little bit of it. It is a great website and nice share. I want to thank you. Good job! You guys do a great blog, and have some great contents. Keep up the good work. รับทำ SEO

28. Hey what a brilliant post I have come across and believe me I have been searching out for this similar kind of post for past a week and hardly came across this. Thank you very much and will look for more postings from you. สมัคร ufabet

29. Hello I am so delighted I located your blog, I really located you by mistake, while I was watching on google for something else, Anyways I am here now and could just like to say thank for a tremendous post and a all round entertaining website. Please do keep up the great work. 오피아트

30. I really appreciate the kind of topics you post here. Thanks for sharing us a great information that is actually helpful. Good day! 오피

31. What a fantabulous post this has been. Never seen this kind of useful post. I am grateful to you and expect more number of posts like these. Thank you very much. 먹튀검증업체

32. Very good points you wrote here..Great stuff...I think you've made some truly interesting points.Keep up the good work. 먹튀폴리스

33. Keep up the good work , I read few posts on this web site and I conceive that your blog is very interesting and has sets of fantastic information. 먹튀검증

34. There is so much in this article that I would never have thought of on my own. Your content gives readers things to think about in an interesting way. Satta king 786

35. I have read your article couple of times because your views are on my own for the most part. It is great content for every reader. 토토사이트

36. Hi there! Nice post! Please tell us when I will see a follow up! 먹튀검증

37. Businesses who utilize plant machinery must be able to provide a plant machinery certificate for all equipment that they have.  abattoir machineries

38. I unquestionably appreciating each and every piece of it and I have you bookmarked to look at new stuff you post. 안전놀이터

39. I've been looking for info on this topic for a while. I'm happy this one is so great. Keep up the excellent work 검증사이트

40. Remarkable article, it is particularly useful! I quietly began in this, and I'm becoming more acquainted with it better! Delights, keep doing more and extra impressive 먹튀검증

41. ค่ายเกมสล็อตออนไลน์ชั้นนำ PG SLOTXO JOKER ทางเว็บ AMBBET ให้คุณได้เล่นเเบบฟรีๆ ทดลองเล่นสล็อตฟรี โดยไม่มีค่าใช้จ่ายสักบาท เล่นได้เลยไม่ต้องโหลด เล่นสนุกรองรับทุกระบบ มีเกมสล็อตให้เลือกเล่นมากกว่า 200 เกม เล่นฟรีโดยไม่ต้องสมัคร ไม่ต้องฝาก เครดิตฟรีไม่อั้น ไม่ต้องเเชร์ รับได้ไม่อั้น เล่นฟรี 24 ชั่วโมง ไม่จำกัดเวลาในการเล่น.