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Bolt heaters perform an essential function in the maintenance of Turbine Generators. The latest designs were developed in conjunction with the CEGB and Turbine manufacturers to meet the exacting requirements of the industry. They are approved to CEGB Standard 12/64.
*Length, loading and diameter are to CEGB Specification – See List. Other diameters, lengths & loadings are available to customer’s specification.
*Connection to the supply is via a Harvey Hubbell plug and socket or alternatively BS4343 or cable connection as an option.
*The fabricated stainless steel terminal box is robust, fitted with a substantial handle and has provision for identification bolt numbers etc.
*The range of heaters is based on two sizes of terminal box.
*The elements are offset in the low profile terminal box for maximum clearance.
*Element bundle replacement can be carried out on site if required – no need to return the heaters for maintenance.
*Supply volts = 110V
*Heaters are fully interchangeable with the range formerly
Manufactured by Redring Electric
 |
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TYPES OF TERMINAL BOX ARRANGEMENT
Arrangements
(see below)
|
Harvey Hubbell
Rating
|
Connector
Type of Harvey Hubbell
Plug required*
Redring ref.
|
I |
30A |
77-666801 |
II |
30A |
77-666801 |
III |
60A |
77-666802 |
IV |
100A |
77-666803 |
* The male plug is not supplied as part of the bolt heater. But can be obtained direct from Elmatic Ltd.
Order under the above numbers separately |
.
Arrgt. |
A |
B |
C |
D |
E |
F |
G |
H |
I |
3½” |
4” |
1¼” |
4½” |
3 5/16” |
5⅝” |
1⅝” |
2¾” |
II |
3½” |
5” |
1⅝” |
6⅜” |
4” |
5⅝” |
1⅝” |
2¾” |
III |
3½” |
5” |
1⅝” |
6⅜” |
4” |
5⅝” |
1½” |
2¾” |
IV |
3½” |
5” |
1⅝” |
6⅜” |
4” |
5⅝” |
1½” |
2¾” |
BOLT DIA
INCHES |
KW RATING/1” RUN/¼HR/STRAIN |
0.15% |
0.22% |
0.30% |
1¾ |
0.0237 |
0.0337 |
0.045 |
2 |
0.0325 |
0.046 |
0.062 |
2¼ |
0.0437 |
0.061 |
0.081 |
2½ |
0.0543 |
0.0767 |
0.101 |
2¾ |
0.0675 |
0.095 |
0.126 |
3 |
0.0806 |
0.113 |
0.151 |
3¼ |
0.0912 |
0.127 |
0.172 |
3½ |
0.106 |
0.148 |
0.200 |
3¾ |
0.123 |
0.173 |
0.232 |
4 |
0.140 |
0.197 |
0.262 |
4¼ |
0.160 |
0.225 |
0.300 |
4½ |
0.181 |
0.255 |
0.340 |
4¾ |
0.202 |
0.287 |
0.383 |
5 |
0.220 |
0.310 |
0.413 |
5¼ |
0.246 |
0.347 |
0.473 |
5½ |
0.273 |
0.386 |
0.515 |
5¾ |
0.305 |
0.430 |
0.575 |
6 |
0.333 |
0.470 |
0.627 |
METHOD OF SELECTING CORRECT SIZE OF HEATER
The Shank length, diameter and hole size of the stud or stud bolt will be known.
The correct % of strain will be as recommended by the Turbine Manufacturer.
- From the table above select the index figure under the appropriate strain for the diameter or bolt to be heated.
- Multiply this index figure by the shank length (portion to be heated) of the bolt. This will give the kW loading of the heater required.
- Using schedule of standard sizes on page 3, find group with the correct heater diameter for the hole diameter in question. Typical radial clearance is 1/32”
- Out of this group, select a heater of the kW loading as calculated in 2 above and with a heated length equal to the shank length of the bolt and a cold length at least equal to the length of cap nut.
- It is possible that a heater with a longer cold length than actually required will have to be used. In this case an adjusting collar of correct size must be ordered to effectively reduce the cold length.
Example:
Data: 4” dia. Stud bolt
1¼ dia. Hole
20” length of Shank
0.22% of Strain
10” long Cap Nut
From chart index figure = 0.197.
Loading = 0.197 x 20 = 3.94, say 4kw
From page 3, 1.1875” is best dia. of bolt heater, i.e. 1/32” radial clearance.
Redring ref. 77-663305 is obvious choice – 4kw x 20” long Heated Length x 15” long Cold Length
Because the Cap Nut is 10” long, Adjusting Collar Size 2 will have to be used set 5” from shoulder of terminal box.
Note:
If a heater of the required kW and heated length cannot be found, use a heater of a lower loading but correct heated length. If this has to be done then the design heating time of 15 minutes will have to be increased to compensate as follows:
Preferred loading = 4kW
Nearest loading available = 3kW
Heating time will be 15 x 4/3 = 20 minutes.
For more detailed information on bolt heater selection – see CEGB Standard 12/64
Complete Bolt Heater Reference |
Heater dia Inches |
Watts |
Blade length Inches |
Cold length Inches |
Heated length
Inches |
Termlbox arrgt.. |
Complete Spare Elt. Bundle reference |
REDRING |
CEGB |
REDRING |
CEBG |
77-662401 |
12/64/003 |
0.625 |
500 |
12 |
8.5 |
3.5 |
I |
77-662301 |
12/64/153 |
77-662402 |
12/64/004 |
0.625 |
500 |
15 |
10 |
5 |
I |
77-662302 |
12/64/154 |
77-662403 |
12/64/018 |
0.625 |
1000 |
15 |
9 |
6 |
I |
77-662303 |
12/64/168 |
77-662404 |
12/64/019 |
0.625 |
1000 |
18 |
10 |
8 |
I |
77-662304 |
12/64/169 |
77-662405 |
12/64/020 |
0.625 |
1000 |
24 |
13 |
11 |
I |
77-662305 |
12/64/170 |
77-662406 |
12/64/036 |
0.265 |
2000 |
24 |
13 |
11 |
I |
77-662306 |
12/64/186 |
77-662407 |
12/64/082 |
0.625 |
5000 |
54 |
9 |
45 |
III |
77-662307 |
12/64/235 |
77-662408 |
12/64/051 |
0.625 |
3000 |
30 |
6 |
24 |
I |
77-668301 |
12/64/203 |
77-662409 |
12/64/034 |
0.625 |
2000 |
25 |
5 |
20 |
I |
77-662309 |
12/64/184 |
77-662410 |
12/64/035 |
0.625 |
2000 |
37 |
7 |
30 |
I |
77-662310 |
12/64/185 |
77-662411 |
12/64/007 |
0.625 |
500 |
26 |
21 |
5 |
I |
77-662311 |
12/64/152 |
77-662412 |
12/64/033 |
0.625 |
2000 |
15 |
4 |
11 |
I |
77-668302 |
12/64/183 |
77-662413 |
12/64/017 |
0.625 |
1100 |
14 |
6 |
8 |
I |
77-668303 |
12/64/167 |
77-662414 |
12/61/843 |
0.625 |
500 |
13 |
8 |
5 |
I |
77-668304 |
12/61/844 |
77-662701 |
12/64/005 |
0.734 |
500 |
15 |
10 |
5 |
I |
77-662601 |
12/64/155 |
77-662702 |
12/64/006 |
0.734 |
500 |
18 |
9 |
9 |
I |
77-662602 |
12/64/156 |
77-662703 |
12/64/021 |
0.734 |
1000 |
15 |
9 |
6 |
I |
77-662603 |
12.64/171 |
77-662704 |
12/64/022 |
0.734 |
1000 |
18 |
10 |
8 |
I |
77-662604 |
12/64/172 |
77-662705 |
12/64/023 |
0.734 |
1000 |
24 |
13 |
11 |
I |
77-662605 |
12/64/173 |
77-662706 |
12/64/024 |
0.734 |
1000 |
34 |
8 |
26 |
I |
77-662606 |
12/64/174 |
77-662707 |
12/64/037 |
0.734 |
2000 |
21 |
11 |
10 |
I |
77-662607 |
12/64/187 |
77-662708 |
12/64/038 |
0.734 |
2000 |
24 |
11 |
13 |
I |
77-662608 |
12/64/188 |
77-662709 |
12/64/039 |
0.734 |
2000 |
33 |
17.5 |
15.5 |
I |
77-662609 |
12/64/189 |
77-662710 |
12/64/040 |
0.734 |
2000 |
42 |
7 |
35 |
I |
77-662610 |
12/64/190 |
77-662711 |
12/64/053 |
0.734 |
3000 |
35 |
15 |
20 |
I |
77-662611 |
12/64/204 |
77-662712 |
12/64/068 |
0.734 |
4000 |
53 |
12 |
41 |
III |
77-662612 |
12/64/218 |
77-663001 |
12/64/099 |
0.875 |
6000 |
48 |
10 |
38 |
III |
77-662901 |
12/64/249 |
77-663002 |
12/64/046 |
0.875 |
2000 |
30 |
9 |
21 |
I |
77-662902 |
12/64/196 |
77-663003 |
12/64/047 |
0.875 |
2000 |
27 |
12 |
15 |
I |
77-662903 |
12/64/197 |
77-663004 |
12/64/060 |
0.875 |
3000 |
20 |
9 |
11 |
I |
77-662904 |
12/64/208 |
77-663005 |
12/64/061 |
0.875 |
3000 |
23 |
9 |
14 |
I |
77-662905 |
12/64/209 |
77-663006 |
12/64/062 |
0.875 |
3000 |
25 |
6 |
19 |
I |
77-662906 |
12/64/210 |
77-663007 |
12/64/076 |
0.875 |
4000 |
30 |
4 |
26 |
III |
77-669001 |
12/64/224 |
77-663008 |
12/64/065 |
0.875 |
3000 |
19 |
6 |
15 |
I |
77-669002 |
12/64/211 |
77-663009 |
12/64/054 |
0.875 |
3000 |
36 |
8 |
28 |
I |
77-662907 |
12/64/213 |
77-663010 |
12/64/044 |
0.875 |
2000 |
18 |
8 |
10 |
I |
77-662908 |
12/64/194 |
77-663011 |
12/64/063 |
0.875 |
3000 |
31 |
7 |
24 |
I |
77-662909 |
12/64/216 |
77-663012 |
12/64/064 |
0.875 |
3000 |
42 |
14 |
28 |
I |
77-662910 |
12/64/217 |
77-663013 |
12/64/059 |
0.875 |
3000 |
34 |
13 |
21 |
I |
77-662911 |
12/64/215 |
77-663014 |
12/64/058 |
0.875 |
3000 |
30 |
15 |
15 |
I |
77-662912 |
12/64/214 |
77-569201 |
12/64/066 |
1.000 |
3000 |
19 |
6 |
14 |
I |
77-664203 |
12/64/212 |
77-669202 |
12/64/041 |
1.000 |
2000 |
13 |
4 |
9 |
I |
77-664202 |
12/64/193 |
HEATER SIZES AND REFERENCE NUMBERS CONTINUED...
Complete Bolt
Heater reference |
Heater Ø
Inches |
Watts |
Blade Length Inches |
Cold Length Inches |
Heated Length Inches |
Term Box
Style. |
Complete Spare Element Bundle references |
REDRING |
CEGB |
REDRING |
CEGB |
77-663301 |
12/64/042 |
1.1875 |
2000 |
24 |
14 |
10 |
II |
77-663201 |
12/64/191 |
77-663302 |
12/64/055 |
1.1875 |
3000 |
24 |
11 |
13 |
II |
77-663202 |
12/64/205 |
77-663303 |
12/64/056 |
1.1875 |
3000 |
35 |
15 |
20 |
II |
77-663203 |
12/64/206 |
77-663304 |
12/64/069 |
1.1875 |
4000 |
24 |
8.5 |
15.5 |
III |
77-663204 |
12/64/219 |
77-663305 |
12/64/070 |
1.1875 |
4000 |
35 |
15 |
20 |
III |
77-663205 |
12/64/220 |
77-663306 |
12/64/086 |
1.1875 |
5000 |
48 |
23 |
25 |
III |
77-663206 |
12/64/236 |
77-663307 |
12/64/100 |
1.1875 |
6000 |
48 |
23 |
25 |
III |
77-663207 |
12/64/250 |
77-663308 |
12/64/101 |
1.1875 |
6000 |
54 |
14 |
40 |
III |
77-663208 |
12/64/251 |
77-663309 |
12/64/113 |
1.1875 |
8000 |
42 |
14 |
28 |
IV |
77-663209 |
12/64/263 |
77-663310 |
12/64/114 |
1.1875 |
8000 |
54 |
19 |
35 |
IV |
77-663210 |
12/64/264 |
77-663311 |
12/64/126 |
1.1875 |
10000 |
54 |
16 |
38 |
IV |
77-663211 |
12/64/276 |
77-663312 |
12/64/127 |
1.1875 |
10000 |
60 |
15 |
45 |
IV |
77-663212 |
12/64/277 |
77-663313 |
12/64/140 |
1.1875 |
11000 |
54 |
16 |
38 |
IV |
77.663213 |
12/64/290 |
77-663314 |
12/64/141 |
1.1875 |
11000 |
60 |
15 |
45 |
IV |
77-663214 |
12/64/291 |
77-663601 |
12/64/043 |
1.375 |
2000 |
18 |
9 |
9 |
II |
77-663501 |
12/64/192 |
77-663602 |
12/64/057 |
1.375 |
3000 |
24 |
14 |
10 |
II |
77-663502 |
12/64/207 |
77-663603 |
12/64/071 |
1.375 |
4000 |
24 |
11.5 |
12.5 |
III |
77-663503 |
12/64/221 |
77-663604 |
12/64/072 |
1.375 |
4000 |
35 |
15 |
20 |
III |
77-663504 |
12/64/222 |
77-663605 |
12/64/087 |
1.375 |
5000 |
28 |
12.5 |
15.5 |
III |
77-663505 |
12/64/237 |
77-663606 |
12/64/128 |
1.375 |
10000 |
45 |
15 |
30 |
IV |
77-663506 |
12/64/278 |
77-663901 |
12/64/073 |
1.438 |
4000 |
24 |
11.5 |
12.5 |
III |
77-663801 |
12/64/223 |
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