When you need to dissipate a few hundred watts to several thousand watts per element, wire or tape wound resistors are the preferred technology. The simple wire wound resistor construction consists of winding a high resistivity material around an insulating core.
Depending on the application we typically wind around a ceramic core with a wire made from a Nickel-Chromium alloy also known as Nichrome wire. Once wound, various terminations are added and the resistance wire is spot welded to these terminals providing electrical contact. Lastly, the assembly can be encapsulated to protect it from adverse conditions such as moisture and physical damage. We encapsulate the resistor by applying several coats of vitreous enamel and then firing to create a durable coating.
In the case of open-type wire wound resistors, these are close wound with an oxidized resistance wire. We supply these with a standard adjustable tapping clip.
Minimizing the temperature coefficient (TCR) is also an important consideration. TCR is the resistance change with temperature and is stated in ppm/°C. For example, a resistor rated at 100ppm/°C, the resistance will not change more than 100O for each 1MO of the resistors' value for a temperature change of 1°C.
LOW CAPACITANCE AND INDUCTANCE WINDING METHOD - AYRTON-PERRY
We offer an Ayrton-Perry winding method for resistors in AC applications. This is especially important in high-frequency designs where low capacitance and inductance are needed. See the below diagram.
The Ayrton-Perry winding is like a simple resistor winding except that two opposing windings are applied to the core. The current in these windings is applied in opposite directions to minimize the inductance. We produce the windings close to each other similar to bifilar windings to reduce the resistors winding capacitance.
AYRTON-PERRY WINDING DIAGRAM
HIGHLY CUSTOMIZABLE AND MEDIUM VOLTAGE OPTIONS
We can provide unique resistance values unmounted and in various mounting options that most other manufacturers will not consider for low quantities.
For medium voltage applications, we manufacture resistors using dielectrics materials and manufacturing techniques suitable for these applications. Our medium voltage resistor designs take into account important parameters such as creepage and clearance distances which are a concern at these voltages.
VITREOUS ENAMELED WIRE WOUND - TYPE PE
Resistors are available in a range from 20 Watts to 500 Watts. Nickel-Chrome wire wound resistor winding is fully protected using several coats of vitreous enamel.
The coated resistor element is fired at a controlled high temperature to produce a highly reliable end product, capable of withstanding adverse conditions. To ensure reliable connections resistors come with terminal tags suitable for screws, and some sizes come with ‘Faston' terminals.
Terminal bands are spot welded in position on the heat resistant ceramic form, and the winding is then spot welded to the connecting terminal before the enameling process. The terminal bands are therefore an integral part of the resistor, protected by the vitreous coating.
PE Type resistors mounting and connection configurations
PE Type - Unmounted Vitreous Enameled Resistors with two standard connection tabs.
PE Type Tapped - Unmounted Vitreous Enameled Resistors with multiple connection tabs.
PE-Adj Type - An adjustable tapping clip included. Moving this clip along an exposed track on the side of the resistor provides a range of resistances.
PE Style -WF - Live Ferrule ends allow for a flexible wire leads to connect to ferrule ends, making this style of resistor suitable for mounting directly into special mounting clips.
PE Style -F - Dead Ferrule ends allow for the resistor to be connected to standard terminal and attaching the ferrules to standard mounting clips.
TB Mounting Style - This configuration is suitable for mounting resistors directly to a panel of 6mm or less in thickness. It consists of cupped washers in each end of the resistor with a tie-rod protruding from each end.
H Mounting Style - L- brackets are used for horizontal mounting, and connection tabs provide the electrical contact. The mounting brackets are attached by tie-rods and fixing nuts to ensure that the resistor will not rotate about its axis.
HR Mounting Style - Similar to “H” above except the horizontal feet are reversed. This is ideal for applications where space is at a premium.
V Mounting Style - This provides vertical mounting by means of a fixed bracket at one end which is appropriate for panel mounting.
OPEN WIRE WOUND – PB TYPE
Resistors are available in a range from 30 Watts to 380 Watts. Open Wire Wound Resistors are close wound with oxidized Nickel-Chrome wire. Each resistor is fitted with an adjustable tapping clip as standard.
To ensure reliable connections resistors come with terminal tags suitable for screws, and some sizes come with ‘Faston' terminals. Terminal bands are spot welded in position on the heat resistant ceramic form, and the winding is then spot welded to the connecting terminal. The terminal bands are an integral part of the resistor.
Standard Ohmic Values 30 to 90 Watts
Standard Ohmic Values & Power Ratings
Series
PB30
PB40
PB45
PB60L
PB60S
PB90L
PB90S
Watts
30
40
45
60
60
90
90
Ohmic Values One Tap
Min.
0R2
0R5
0R3
0R5
0R4
0R5
0R4
Max.
510R
1K0
720R
1K3
1K3
2K1
2K1
Standard Ohmic Values 130 to 380 Watts
Standard Ohmic Values & Power Ratings
Series
PB130
PB150
PB180
PB220
PB320
PB380
Watts
130
150
180
220
320
380
Ohmic Values One Tap
Min.
0R4
0R5
0R7
0R7
1R0
1R2
Max.
3K2
4K0
5K2
6K8
9K8
11K5
Dimensional Charts - Open Wire Wound Resistors
The following mounting configurations are available for PB style resistors
TB Mounting Style - This configuration is suitable for mounting resistors directly to a panel of 6mm or less in thickness. It consists of cupped washers at each end of the resistor with a tie-rod protruding from each end.
H Mounting Style - L- brackets are used for horizontal mounting, and connection tabs provide the electrical contact. The mounting brackets are attached by tie-rods and fixing nuts to ensure that the resistor will not rotate about its axis.
HR Mounting Style - Similar to “H” above except the horizontal feet are reversed. This is ideal for applications where space is at a premium.
V Mounting Style - This provides vertical mounting utilizing a fixed bracket at one end which is appropriate for panel mounting.
HEAVY DUTY VITREOUS ENAMELED TAPE WOUND RESISTORS – PT TYPE
Continuous Power Ratings are available from 250 Watts to 1000 Watts. For pulse ratings, refer to the "Continuous & Intermittent" and "Continuous & Short Term" Power Rating tables below.
The resistor winding is fully protected using several coats of vitreous enamel. The coated resistor element is fired at a controlled high temperature to produce a highly reliable resistor, capable of withstanding adverse conditions. Resistors are edge-wound with corrugated tape for low Ohmic Values.
Improved heat dissipation because of the increased surface area using corrugated tape wound resistors provides a power rating, up to approximately 25% greater than that of the equivalent wire wound resistor. We provide our tape-wound resistors with an adjustable tapping clip.
When needed to prevent circuit overloads we provide resistors fitted with thermal cut-outs. These operate a contact disconnecting the resistor from the circuit. The minimum and maximum resistance values given below are available within a range of standard resistance alloy. Upon request, we supply resistors in a Heavy-Duty Enclosure.
Power Ratings: Continuous & Intermittent
Power Ratings: Continuous & Intermittent
Part Number
Continuous
Intermittent (Seconds)
Ohmic Values
30
60
120
180
240
300
Min.
Max.
PT200H
250
1375
825
625
500
375
310
0.6
25
PT300H
400
2200
1320
1000
800
600
500
0.6
30
PT400H
525
2900
1730
1310
1050
785
655
1
30
PT450H
600
3300
1980
1500
1200
900
750
1.5
40
PT600H
800
4400
2640
2000
1800
1200
1000
3
60
PT750H
1000
5500
3300
2500
2000
1500
1250
3.5
100
Operating Time in any 15 Minute Period
Power Ratings: Continuous & Short Term
Power Ratings: Continuous & Short Term
Part Number
Continuous
Short Term (Seconds)
Ohmic Values
5
10
20
Min.
Max.
PT200H
250
5000
3750
2250
0.6
25
PT300H
400
8000
6000
3600
0.6
30
PT400H
525
10500
7875
4700
1
30
PT450H
600
12000
9000
5400
1.5
40
PT600H
800
16000
12000
7200
3
60
PT750H
1000
20000
15000
9000
3.5
100
Operating 1x Per Hour
Enameled Heavy Duty Tape Wound Resistors
Enameled Heavy Duty Tape Wound Resistors
Part Number
Dimensions (mm)
Watts
A
B
C
D
E
F
G
H
J
K
L
PT200H
250
152
44
29
43
9.5
5
190
173
44
51
7 x 14
PT300H
400
203
44
29
43
9.5
5
241
223
44
51
7 x 14
PT400H
525
254
44
29
43
9.5
5
292
274
44
51
7 x 14
PT450H
600
305
44
29
43
9.5
5
343
325
44
51
7 x 14
PT600H
800
305
54
38
50
9.5
5
356
333
54
76
7 x 17
PT750H
1000
356
54
38
50
9.5
5
406
384
54
76
7 x 17
PT Type resistors mounting and connection configurations
H Mounting Style - L- brackets are used for horizontal mounting, and connection tabs provide the electrical contact. The mounting brackets are attached by tie-rods and fixing nuts to ensure that the resistor will not rotate about its axis.
HR Mounting Style - Similar to “H” above except the horizontal feet are reversed. This is ideal for applications where space is at a premium.
HEAVY DUTY OPEN TAPE WOUND RESISTORS – PHD TYPE
Continuous Power Ratings are available from 200 Watts to 7500 Watts. For pulse ratings, refer to the "Continuous & Intermittent" and "Continuous & Short Term" Power Rating tables below. On these edgewound power resistors, the power rating can be greater than that of the equivalent wire-wound resistor, due to the increased heat dissipation provided by the tape. We provide an option with Tape-wound resistors for an adjustable tapping clip.
We can quickly supply direct replacements for difficult values to obtain in the PFE series edgewound or EDGF edgewound power resistors. Thermal Cut-outs are mounted to some resistors to operate a contact to disconnect the resistor from the circuit preventing overload damage. The minimum and maximum resistance values are below in a variety of standard resistance alloys. Upon request, we supply resistors in a Heavy-Duty Enclosure.
Power Ratings: Continuous & Intermittent
Power Ratings: Continuous & Intermittent
Part Number
Continuous
Intermittent (Seconds)
Ohmic Values
30
60
120
180
240
300
Min.
Max.
PHD200
200 Watts
1100 Watts
660 Watts
500 Watts
400 Watts
300 Watts
250 Watts
0.45
872
PHD300
300 Watts
1650 Watts
990 Watts
750 Watts
600 Watts
450 Watts
375 Watts
0.67
1294
PHD400
400 Watts
2200 Watts
1320 Watts
1000 Watts
800 Watts
600 Watts
500 Watts
0.9
1700
PHD450
450 Watts
2500 Watts
1500 Watts
1130 Watts
900 Watts
690 Watts
570 Watts
1.06
2100
PHD600
600 Watts
3200 Watts
1930 Watts
1460 Watts
1170 Watts
880 Watts
740 Watts
1.35
2600
PHD750
750 Watts
4000 Watts
2420 Watts
1830 Watts
1460 Watts
1100 Watts
920 Watts
1.6
3100
Operating Time in any 15 Minute Period
With Tap
Power Ratings: Continuous & Short Term
Power Ratings: Continuous & Short Term
Part Number
Continuous
Short Term (Seconds)
Ohmic Values
5
10
20
Min.
Max.
PHD200
200 Watts
4000 Watts
3000 Watts
1800 Watts
0.45
872
PHD300
300 Watts
6000 Watts
4500 Watts
2700 Watts
0.67
1294
PHD400
400 Watts
8000 Watts
6000 Watts
3600 Watts
0.9
1700
PHD450
450 Watts
9000 Watts
6700 Watts
4000 Watts
1.06
2100
PHD600
600 Watts
12300 Watts
9200 Watts
5500 Watts
1.35
2600
PHD750
750 Watts
14700 Watts
11000 Watts
6600 Watts
1.6
3100
Operating 1x Per Hour
With Tap
Open Wound Heavy Duty Resistors
Open Wound Heavy Duty Resistors
Part Number
Dimensions (mm)
Watts
A
B
C
D
E
F
G
H
J
K
L
PHD200
200
152
44
29
43
9.5
5
190
173
44
51
7 x 14
PHD300
300
203
44
29
43
9.5
5
241
223
44
51
7 x 14
PHD400
400
254
44
29
43
9.5
5
292
274
44
51
7 x 14
PHD450
450
305
44
29
43
9.5
5
343
325
44
51
7 x 14
PHD600
600
305
54
38
50
9.5
5
356
333
54
76
7 x 17
PHD750
750
356
54
38
50
9.5
5
406
384
54
76
7 x 17
The following mounting configurations are available for PHD style resistors
H Mounting Style - L- brackets are used for horizontal mounting, and connection tabs provide the electrical contact. The mounting brackets are attached by tie-rods and fixing nuts to ensure that the resistor will not rotate about its axis.
HR Mounting Style - Similar to “H” above except the horizontal feet are reversed. This is ideal for applications where space is at a premium.
Other Mounting Options
Clips for Ferrule Ended Resistors - These clips are manufactured from Stainless Steel and are suitable for live or dead ferrule ended resistors.
Push-In Mounting Brackets - Spring fit nickel plated phosphor bronze brackets for the ends of the tubular resistor provide an inexpensive method of mounting. They are available for PE 30, PE 40, PE 60L and PE 90L, but should not be used where rotation of the resistor in the clip is undesirable.
RESISTOR ENCLOSURES
Countinuous Power Ratings are available from 200 Watts to 7500 Watts. For pulse ratings, refer to the "Continuous & Intermittent" and "Continuous & Short Term" Power Rating tables below.
On this type of resistor, the power rating can be greater than that of the equivalent wire-wound resistor, due to the increased heat dissipation provided by the tape. We provide an option with Tape-wound resistor for an adjustable tapping clip. Thermal Cut-outs are mounted to some resistors to operate a contact to disconnect the resistor from the circuit preventing overload damage.
The minimum and maximum resistance values are below in a variety of standard resistance alloys. Upon request, we supply resistor in a Heavy-Duty Enclosure.
Power Ratings: Continuous, Short Term & Intermittent
Power Ratings: Continuous, Short Term & Intermittent
