Tubular Vitreous Enamelled
Tubular Vitreous Enamelled
Wirewound Resistors
Wirewound Resistors
1600/1900 Series
1600/1900 Series
Welwyn Components
·
·
·
·
Impervious lead free vitreous enamel coating
Impervious lead free vitreous enamel coating
Can be supplied with fixed, adjustable, tapped or
Can be supplied with fixed, adjustable,
low inductance winding
tapped or low inductance winding
Seven termination styles with choice of
Seven termination styles with choice of
mounting arrangements
mounting arrangements
Manufactured RoHS compliant Pb-free terminations*
Manufactured RoHS compliant
* Check status of stock when ordering
Pb-free terminations*
* Check status of stock when ordering
General Information
Vitreous enamelled wirewound resistors are capable of
withstanding a higher dissipation size for size, than any other
protected type; this is attributable to the higher operating
temperature which the wire and enamel can withstand.
Vitreous enamel provides exceptionally good protection to the
wire element and is essentially impervious to moisture. The
resistors can safely be used in harsh environmental conditions.
The Welwyn range is based on thirteen sizes of tube, each of
which has a recommended maximum dissipation which limits
operating surface temperature to a maximum of 375°C.
The stability and high reliability of Welwyn tubular vitreous
resistors is a direct result of the best quality materials being
used in their construction.
High purity ceramic tubes have been matched with nickel
chromium resistance wires and specially formulated enamel to
ensure that the resistors can withstand repeated heat cycling
without damage.
Connections between the resistance element and end
terminations are welded; other connections are brazed.
Mounting devices are available which permit resistors to be
mounted by both ends or by one end. Single ended mounting
is recommended for applications which do not subject the
resistor to shock or vibration.
Ferrules and the F type mounting plug are anchored into the
tubes with high temperature adhesive.
Special requirements, for types or styles not described
in this brochure, will be considered for economic
quantities.
Electrical Data
Power rating at 70°C
Resistance range
Limiting element voltage
TCR (-55 to +200°C)
Resistance tolerance
Values
Thermal impedance
Operating temperature range
watts
ohms
volts
ppm/°C
%
°C/watt
°C
1605
47
1601
11
1905
16
1602
1906
1603
1604
17
22
25
35
See Table 1
See Table 1
Typically: <+75
Maximum + 200
1, 2, 5, 10
See table 1 for value restrictions
E24 preferred
See fig. 1
-55 to +375
1908
54
1607
1606
76
91
See Table 1
See Table 1
1608
115
1609
165
1600
16.5
Power rating at 70°C
Resistance range
Limiting element voltage
TCR (-55 to +200°C)
Resistance tolerance
Values
Thermal impedance
Operating temperature range
watts
ohms
volts
ppm/°C
%
°C/watt
°C
Typically: <+75
1, 2, 5, 10
Maximum + 150
See table 1 for value restrictions
E24 preferred
See fig. 1
- 55 to +375
Note
See Figure 1 for curves of temperature rise / watts dissipation.
General Note
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
TT electronics reserves the right to make changes in product specification without notice or liability.
A subsidiary of
All information is subject to Welwyn’s own data, relates to current manufacture and is considered accurate at time of going to print.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
TT electronics plc
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
09.0
Telephone: +44 (0) 1670
© TT electronics plc
822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
08. 11
121
Tubular
Vitreous Enamelled
Tubular Vitreous Enamelled
Tubular
Vitreous Enamelled
Wirewound Resistors
Wirewound Resistors
Wirewound Resistors
1600/1900 Series
1600/1900
Series
1600/1900
Series
Series
Welwyn Components
Welwyn Components
Welwyn Components
Electrical Data
(continued)
Electrical Data
(continued)
(continued)
Table 1 1
Table 1
Table
*Dissipation (watts) to
*Dissipation (watts) to
*Dissipation (watts) to
produce operating
produce operating
produce operating
hotspot temperature (°C) of:
hotspot temperature (°C) of:
hotspot temperature (°C) of:
Ambient = 20°C
Ambient
Ambient = 20°C
Ambient
Ambient = 20°C
Ambient
= 70°C
= 70°C
= 70°C
Type
Type
Type
1601
1601
1601
1905
1905
1905
1600
1600
1600
1602
1602
1602
1906
1906
1906
1603
1603
1603
1604
1604
1604
1605
1605
1605
1908
1908
1908
1607
1607
1607
1606
1606
1606
1608
1608
1608
1609
1609
1609
Resistance range (ohms)
Resistance range (ohms)
Resistance range (ohms)
Limiting
Limiting
Limiting
element
element
element
voltage
voltage
voltage
Termination
Termination
Termination
style
style
style
Low inductance
Low inductance
Low inductance
winding resistance
winding resistance
winding resistance
range (ohms)
range (ohms)
range (ohms)
Min. res. at
Min. res. at
Min. res. at
Max. at
Max. at
Max. at
either
either
either
±5%
tolerance
±5%
tolerance
±5%
tolerance
50
1.3k
50
1.3k
50
1.3k
50
3.5k
50
3.5k
50
3.5k
50
5.0k
50
5.0k
50
5.0k
50
4.0k
50
4.0k
50
4.0k
50
5.5k
50
5.5k
50
5.5k
50
7.5k
50
7.5k
50
7.5k
50
11.5k
50
11.5k
50
11.5k
50
14k
50
14k
50
14k
50
16k
50
16k
50
16k
50
22k
50
22k
50
22k
50
32k
50
32k
50
32k
50
38k
50
38k
50
38k
100
58k
100
58k
100
58k
Minimum
Minimum
Minimum
resistance at
resistance at
resistance at
*The stated dissipation applies toto resistors mounted horizontally with unobstructed bore.
resistors mounted horizontally with unobstructed bore.
*The stated dissipation applies to resistors mounted horizontally with unobstructed bore.
*The stated dissipation applies
200
200
200
5
5
5
7
7
7
7.5
7.5
7.5
8
8
8
9.5
9.5
9.5
11
11
11
15.5
15.5
15.5
21
21
21
24
24
24
34
34
34
41
41
41
52
52
52
74
74
74
300
300
300
10
10
10
14.5
14.5
14.5
15
15
15
15.5
15.5
15.5
19
19
19
22
22
22
31
31
31
41
41
41
47
47
47
66
66
66
80
80
80
101
101
101
145
145
145
375
375
375
14
14
14
20
20
20
21
21
21
22
22
22
28
28
28
32
32
32
45
45
45
59
59
59
68
68
68
95
95
95
115
115
115
145
145
145
208
208
208
375
375
375
11
11
11
16
16
16
16.5
16.5
16.5
17
17
17
22
22
22
25
25
25
35
35
35
47
47
47
54
54
54
76
76
76
91
91
91
115
115
115
165
165
165
±5%
±5%
±5%
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
±2%
±2%
±2%
15
15
15
15
15
15
15
15
15
20
20
20
20
20
20
20
20
20
20
20
20
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
35
35
35
Max. at
Max. at
Max. at
any
any
any
±1%
tolerance
±1%
tolerance
±1%
tolerance
25
15k
25
15k
25
15k
30
30k
30
30k
30
30k
30
56k
30
56k
30
56k
25
43k
25
43k
25
43k
30
50k
30
50k
30
50k
30
83k
30
83k
30
83k
60
100k
60
100k
60
100k
40
100k
40
100k
40
100k
40
100k
40
100k
40
100k
50
100k
50
100k
50
100k
40
160k
40
160k
40
160k
50
180k
50
180k
50
180k
50
250k
50
250k
50
250k
C
C
250
250
250
-
-
-
-
-
-
500
500
500
700
700
700
850
850
850
1300
1300
1300
1100
1100
1100
1200
1200
1200
1300
1300
1300
2100
2100
2100
2100
2100
2100
3000
3000
3000
C
All others ±10%
All others ±10%
All others ±10%
150
10
150
10
150
10
450
10
450
10
450
10
600
10
600
10
600
10
350
10
350
10
350
10
550
10
550
10
550
10
750
10
750
10
750
10
1000
15
1000
15
1000
15
900
15
900
15
900
15
1000
10
1000
10
1000
10
900
15
900
15
900
15
1900
15
1900
15
1900
15
1800
20
1800
20
1800
20
2500
30
2500
30
2500
30
Performance Data
Performance Data
Load : 1000 hours at 70°C
Load : 1000 hours at 70°C
Load : 1000 hours at 70°C
Shelf life : 12 months at room temperature
Shelf life : 12 months at room temperature
Shelf life : 12 months at room temperature
Climatic
Climatic
Climatic
Long term damp heat
Long term damp heat
Long term damp heat
Bump and vibration
Bump and vibration
Bump and vibration
Noise (in a decade of frequency)
Noise (in a decade of frequency)
Noise (in a decade of frequency)
Pulse Handling Data
Pulse Handling Data
Pulse Handling Data
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
Max
Max
Max
5.0
5.0
5.0
1.0
1.0
1.0
0.5
0.5
0.5
0.2
0.2
0.2
0.1
0.1
0.1
zero
zero
zero
Available by request
Available by request
Available by request
Typ
Typ
Typ
3.5
3.5
3.5
0.1
0.1
0.1
0.35
0.35
0.35
0.05
0.05
0.05
0.02
0.02
0.02
zero
zero
zero
General Note
TT electronics reserves the right to make changes in product specification without notice or liability.
©
All information is subject to TT
Limited
Bedlington, Northumberland
accurate at time of going to print.
Welwyn Components
electronics’ own data and is considered
NE22 7AA, UK
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
© Welwyn
(0) 1670 822181 · Facsimile: +44 (0) 1670 Northumberland info@welwyn-tt.com · Website: www.welwyn-tt.com
© Welwyn Components Limited
Bedlington, 829465 · Email: NE22 7AA, UK
Telephone: +44
Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
© TT electronics plc
08. 11
122
122
122
Tubular Vitreous Enamelled
Wirewound Resistors
Tubular Vitreous Enamelled
Tubular
Series
Vitreous Enamelled
1600/1900
Wirewound Resistors
Wirewound Resistors
1600/1900 Series
Welwyn Components
Welwyn Components
1600/1900 Series
Physical Data
Table 2 Dimensions in millimetres. See fig 2-8 for styles
A
B
C
D
E
F
max
19.5
F
17.5
max
19.5
17.5
17.5
19.5
17.5
19.5
19.5
19.5
19.5
19.5
19.5
26.5
Physical Data
1601
1905
Type
1601
1600
1905
1602
1600
1906
1602
1603
1906
1604
1603
1605
1604
Table 2 Dimensions in millimetres. See fig 2-8 for styles
Type
max
max
max
nom
max
33.0
A
56.1
max
33.0
61.5
56.1
51.0
61.5
64.3
51.0
74.5
64.3
102
74.5
89.5
G
nom
15
G
10
nom
15
10
10
15
10
15
15
15
15
15
15
17
H
±.25
3.0
H
3.0
±.25
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
4.0
J
M3
J
M3
M3
M3
M3
M3
M3
M3
M3
M3
M3
M4
K
max
59
K
-
max
59
-
-
77
-
90
77
101
90
128
101
122
128
122
134
134
198
184
248
17.5
B
14.5
max
17.5
14.5
14.5
17.5
14.5
17.5
17.5
17.5
17.5
17.5
17.5
24.0
8.2
C
6.55
max
8.2
6.55
6.55
8.2
6.55
8.2
8.2
8.2
8.2
8.2
8.2
13.2
8.2
13.2
13.2
19.2
13.2
13.2
19.2
19.2
13.2
19.2
19.2
19.2
4.5
D
4.5
nom
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.5
5.7
5.0
E
5.0
max
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
6.8
1908
1605
1607
1908
1606
1607
1608
1606
1609
1608
1609
102
89.5
102
102
166
102
152
166
216
152
216
102
24.0
24.0
32.0
24.0
24.0
32.0
32.0
24.0
32.0
32.0
32.0
17.5
5.7
5.7
7.0
5.7
5.7
7.0
7.0
5.7
7.0
7.0
7.0
4.5
6.8
6.8
9.8
6.8
6.8
9.8
9.8
6.8
9.8
9.8
9.8
5.0
26.5
26.5
32.0
26.5
26.5
32.0
32.0
26.5
32.0
32.0
32.0
19.5
17
17
22
17
17
22
22
17
22
22
22
15
4.0
4.0
6.4
4.0
4.0
6.4
6.4
4.0
6.4
6.4
6.4
3.0
M4
M4
M6
M4
M4
M6
M6
M4
M6
M6
M6
M3
134
134
198
184
248
Terminations
Terminations
Styles B, 4B, AP and AW are available in all 13 tube sizes.
Styles C, CB and CP are available in sizes 1601 to 1609
Ferrule, electrically isolated (Figure 6) Connection to
resistor via Pb free solder coated nickle iron lugs. Denoted
resistor via Pb free solder coated nickle iron lugs. Denoted
by prefix CB, thus: CB1602.
by prefix CB, thus: CB1602.
Styles B, 4B, AP and AW are available in all 13 tube sizes.
Styles C, CB and CP are available in sizes 1601 to 1609
inclusive, 1906 and 1908
inclusive, 1906 and 1908
Ferrule, electrically isolated (Figure 6) Connection to
Lugs (Figure 2): Pb free solder coated nickel iron. Denoted
Lugs (Figure 2): Pb free solder coated nickel iron. Denoted
by prefix B to size reference, thus B1602
by prefix B to size reference, thus B1602
Pigtails (Figure 3): 14/.193 mm copper, 150 mm minimum
Pigtails (Figure 3): 14/.193 mm copper, 150 mm minimum
length. Denoted by prefix AP, thus AP1602
length. Denoted by prefix AP, thus AP1602
Rigid wires (Figure 4): 1.2 mm diameter tinned copper, 32
mm minimum length.
Denoted by prefix AW, thus: AW1602
Lugs with screws, nuts and washers (Figure 5): Nickel
plated brass screws and nuts. Denoted by prefix 4B,
plated brass screws and nuts. Denoted by prefix 4B,
thus: 4B1602.
thus: 4B1602.
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Ferrule, electrically live (Figure 7) Nickel plated brass.
Ferrule, electrically live (Figure 7) Nickel plated brass.
Denoted by prefix C, thus: C1602.
Denoted by prefix C, thus: C1602.
Ferrule, electrically isolated (Figure 8): Connection to
Ferrule, electrically isolated (Figure 8): Connection to
resistor via pigtails of 14/.193 mm copper, 150mm
resistor via pigtails of 14/.193 mm copper, 150mm
minimum length. Denoted by prefix CP thus: CP1602
Marking The resistors are legend marked with type
reference, resistance value, tolerance and manufacturing
date code. Value marking conforms to IEC 62.
Solvent resistance: The vitreous coating and marking are
resistant to all accepted industrial cleaning fluids.
resistant to all accepted industrial cleaning fluids.
General Note
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670
right to
Facsimile: +44 (0) 1670
specification without notice or liability.
TT electronics reserves the
822181 ·
make changes in product
829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
123
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
123
© TT electronics plc
08. 11
Tubular Vitreous Enamelled
Tubular Vitreous Enamelled
Tubular Vitreous Enamelled
Tubular Vitreous Enamelled
Wirewound Resistors
Wirewound Resistors
Wirewound Resistors
Wirewound Resistors
1600/1900 Series
1600/1900 Series
1600/1900 Series
1600/1900 Series
1600/1900 Series
Adjustable Resistors
(see Figure 9)
Adjustable Resistors
(see Figure 9)
Adjustable resistors use the same basic construction as fixed
Adjustable Resistors
(see Figure 9)
Adjustable Resistors
(see Figurea9)
Adjustable resistors use the and have window in the vitreous
resistors already described, same basic construction as fixed
Adjustable resistors use the and have a window in the vitreous
Adjustable resistors usecontact is made construction as fixed
resistorsthrough described, same basic construction as fixed
enamel already which the same basic to the resistive
resistorsthrough described, and is madewindow in the vitreous
resistors already described, and have a window fitted with a
enamel by a sliding contact band. The to the in the
element already which contact have a band isresistivevitreous
enamel through which contact is made band isresistive
enamel through and nut to retain made to in position. with a
element screw which contact is it firmly the fitted
clampingby a sliding contact band. The to the resistive
element by a sliding nut to retain it The bandposition. with a
element by a sliding contact band. The band is fitted with a
contact
clamping screwwinding style band. maximum is fitted
The adjustable and nut to retainait firmly in position.
has
permissible hot
clamping screw and nut to retain it firmly in position.
clamping screwwinding style has a maximum permissible hot
and
firmly in
The adjustable
spot temperature of 300°C and the maximum dissipation, for
The adjustable winding style hasthe maximum dissipation, for
Theambient temperaturestyle has ais specified permissible The
spotadjustable winding of 20°C,a maximum permissible hot
an temperature of 300°C and maximum in Table 4. hot
spot temperature of 300°C 20°C, is maximumin Table 4. The
spot temperature of 300°C and the maximum dissipation, for
an ambient temperature of and the specified dissipation, for
an ambient temperature of 20°C, is specified in Table 4. The
an ambient
Table 3
temperature of 20°C, is specified in Table 4. The
Welwyn
Welwyn
Welwyn
Welwyn
Components
Components
Components
Components
partial open winding necessitates a reduced maximum
partial open winding necessitatesfixed resistors, and the
resistance, when compared with a reduced maximum
partial open winding necessitatesfixed resistors, and the
partial open winding necessitates Table 4.
resistance,range is also defined in a reduced maximum
resistance when compared with a reduced maximum
resistance,range is also defined in Table 4.
resistance, when compared with fixed resistors, and the
the
resistance when compared with fixed resistors, andthe
More thanrangeadjusting band canTable 4. up to
one
be fitted,
resistance range is also defined in Table 4.
resistance
is
in
More thannumber also definedTable 3.fitted, up to the
maximum one adjusting band can be
specified in
More thannumber specified in Table 3.fitted, up to the
More than one adjusting band can be
one adjusting band can
to the
maximum resistors are available in be fitted, upstyles B, 4B,
Adjustablenumber specified in Table 3.
termination
maximum number specified in Table 3.
maximum
Adjustableand CP, inare availableto 1609 inclusive and B, 4B,
AP, C, CB resistors sizes 1602 in termination styles 1906
Adjustableand CP, inare availableto 1609 inclusive and B, 4B,
Adjustable resistors sizes 1602
AP, C, CB denoted by prefix ‘V’. in termination styles B, 4B,
and 1908 resistors are available in termination styles 1906
AP, C, CB and CP, in sizes 1602 to 1609 inclusive and 1906
AP, 1908 denoted by prefix ‘V’.
andC, CB and CP, in sizes 1602 to 1609 inclusive and 1906
and 1908 denoted by prefix ‘V’.
and 1908 denoted by prefix ‘V’.
Table 3
Table 3
Tube
Table 3
Tube
size
Tube
Tube
size
size
size
1602
A mm
A mm
max.
A mm
A mm
max.
max.
max.
20
20
20
20
20
20
25
20
20
25
25
25
25
25
30
25
25
30
30
30
30
30
30
30
30
30
30
30
B mm
B mm
max.
B mm
B mm
max.
max.
max.
27
27
27
27
27
27
32
27
27
32
32
32
32
32
38
32
32
38
38
38
38
38
38
38
38
38
38
38
Hole C
Hole C
dia. mm
Hole C
Hole C
dia. mm
dia. mm
dia. mm
3.2
3.2
3.2
3.2
3.2
3.2
3.7
3.2
3.2
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
Table
Table
Table
Table
Type
Type
Type
Type
1602
1602
1906
1602
1602
1906
1603
1906
1906
1603
1604
1603
1603
1604
1605
1604
1604
1605
1908
1605
1605
1908
1607
1908
1908
1607
1606
1607
1607
1606
1608
1606
1606
1608
1609
1608
1608
1609
1609
1609
1602
1603
1602
1602
1603
1906
1603
1603
1906
1604
1906
1906
1604
1605
1604
1604
1605
1908
1605
1605
1908
1606
1908
1908
1606
1607
1606
1606
1607
1608
1607
1607
1608
1609
1608
1608
1609
1609
1609
Max. no of
Max. no of
adjusting
Max. no of
Max. no of
adjusting
bands
adjusting
adjusting
bands
bands
bands
1
1
1
1
3
3
2
3
3
2
4
2
2
4
2
4
4
2
3
2
2
3
5
3
3
5
5
5
Resistance range
Resistance range
Resistance range
Resistance range
Min. for
Min. for
all other
Min. for
Min. for
all other
styles
all other
all other
styles
3
styles
styles
3
3
3
3
3
6
3
3
6
8
6
6
8
6
8
8
6
10
6
6
10
9
10
10
9
13
9
9
13
16
13
13
16
24
16
16
24
24
24
(ohms)
(ohms)
(ohms)
(ohms)
4
4
4
4
Max. dissipation in
Max. dissipation in
20°C ambient (watts)
Max. dissipation in
Max. dissipation in
20°C ambient (watts)
20°C ambient (watts)
20°C ambient (watts)
200°C
300°C
200°C
hot spot
200°C
200°C
hot 8
spot
hot spot
hot 8
spot
9.5
8
8
9.5
11
9.5
9.5
11
16
11
11
16
21
16
16
21
24
21
21
24
34
24
24
34
41
34
34
41
52
41
41
52
74
52
52
74
74
74
300°C
hot spot
300°C
300°C
hot spot
15.5
hot spot
hot spot
15.5
19
15.5
15.5
19
22
19
19
22
31
22
22
31
41
31
31
41
47
41
41
47
66
47
47
66
80
66
66
80
101
80
80
101
145
101
101
145
145
145
Min. for
Min. VC,
styles for
Min. for
Min. VC,
styles for
VCP
styles VC,
styles VC,
VCP
4
VCP
VCP
4
4
4
4
4
6
4
4
6
8
6
6
8
6
8
8
6
11
6
6
11
11
11
11
11
14
11
11
14
17
14
14
17
25
17
17
25
25
25
Max. for
Max. for
all styles
Max. for
Max. for
all styles
all styles
all1.6k
styles
1.6k
2.5k
1.6k
1.6k
2.5k
3.0k
2.5k
2.5k
3.0k
5.3k
3.0k
3.0k
5.3k
4.5k
5.3k
5.3k
4.5k
7.5k
4.5k
4.5k
7.5k
8.1k
7.5k
7.5k
8.1k
13.2k
8.1k
8.1k
13.2k
15.4k
13.2k
13.2k
15.4k
25.5k
15.4k
15.4k
25.5k
25.5k
25.5k
Manufactured Values
Manufactured Values
E24 preferred
Manufactured Values
Manufactured Values
E24 preferred
E24 preferred
E24 preferred
Standard Selection Tolerance ±10%
Standard Selection Tolerance
environmental
All other details of the electrical and
±10%
Standard Selection Tolerance
environmental
Standard Selection Tolerance ±10%
All other details adjustable resistors are the same as for
performance of of the electrical and
±10%
All other details adjustable resistors are the same as for
All other details of the electrical and environmental
performance of of the electrical and environmental
fixed resistors.
performance of adjustable resistors are the same as for
performance of adjustable resistors are the same as for
fixed resistors.
fixed resistors.
fixed resistors.
General Note
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
TT electronics reserves the right to make changes in product specification without notice or liability.
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com ·
print.
All information
Components Limited
Bedlington, Northumberland NE22
at time of going to
Website: www.welwyn-tt.com
© Welwyn
is subject to TT electronics’ own data and is considered accurate
7AA, UK
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
124
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
© TT electronics plc
822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Telephone: +44 (0) 1670
124
08. 11
124
124
Tubular Vitreous Enamelled
Tubular Vitreous Enamelled
Wirewound Resistors
Wirewound Resistors
1600/1900 Series
1600/1900 Series
Welwyn Components
Ordering Procedure
Enquiries for tapped resistors must state the following details:
Resistance per section
Maximum dissipation per section
Maximum operating ambient temperature
Maximum permissible dimensions if important
Type of terminations required. (See ‘Terminations’, page 3)
Resistor style or proposed method of mounting.
Tapped Resistors
See Figure 10
Fixed resistors can be supplied with taps to special order.
Because of the reduced winding length, the total resistance of
a tapped resistor will be less than can be offered on a fixed
resistor of the same size. The reduction is proportional to the
number of taps and Table 5 is intended as a guide.
The minimum resistance per section on all sizes is 1Ω and the
standard selection tolerance for any section is ±10%
Table 5
Maximum*
total
dissipation
in 20°C
ambient
(watts) with
single tap
14.5
15.0
15.5
19.0
22
31
41
47
66
80
101
145
Maximum*
resistance
with single
tap
(ohms)
Maximum*
number
of taps
Type
1905
1600
1602
1906
1603
1604
1605
1908
1607
1606
1608
1609
9k
12k
9k
13k
18k
29k
34k
38k
53k
78k
93k
140k
1
1
1
1
1
2
2
2
2
4
4
4
*Maximum total dissipation assumes that this will be
evenly spread over the total element length.
Low Inductance Resistors
Ayrton-Perry wound elements are supplied for low inductance
applications. This winding style has a maximum permissible
hot spot temperature of 300°C. The maximum dissipation is
defined in Table 1 under the heading Operating hot spot
temperature of 300°C, and resistance ranges are defined in
the three right-hand columns of this table.
The recommended dissipations for each of the resistor hot
spot temperatures applies to resistors mounted horizontally. If
the bore is completely blocked a 15% derating is
recommended. However, wherever possible, resistors should
be mounted vertically with unobstructed bore.
This makes best use of the chimney effect of the heated tube
and will encourage a cooling stream of air through the bore.
Allowances must be made, when tubular resistors are mounted
in banks, for the effects produced by radiation between tubes.
Appreciable reduction of hot spot temperature can be
achieved by arranging that resistors are subjected to some
measure of forced draught. In general, it is most efficient to
extract air from the resistor enclosure and arrange that an air
inlet is adjacent to the bottom of the tubes.
If soft soldered connections are used the resistors should be derated
where applicable to limit the hot spot temperature to 300°C.
Application Notes
When cold, vitreous enamel has excellent insulation resistance.
In common with all insulants the specific resistance of the
enamel decreases with increased temperature; therefore, if
operated at any temperature approaching the maximum, the
resistor cannot be classed as an insulated type and should not
be used in contact with any conducting materials.
General Note
TT electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
© TT electronics plc
822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Telephone: +44 (0) 1670
08. 11
123
