GENERAL

   
 

HVR Rod and Tube Resistors are manufactured from a carefully selected mixture of clays, alumina and carbon. After blending, the material is extruded into the required shape and then fired, in a controlled atmosphere, at high temperature.

 
 
 
 
 
 
 

Aluminium is then flame sprayed onto the barrel surfaces (as standard)  to provide electrical contact.

Alternative metallised contacts and corona shielded terminals are also available.

Rod and Tube Resistors are available with Outside Diameters ranging from 10mm to 50mm and in Lengths up to 600mm.

 

With High Surge Energy Rating and Low Inductance, typical applications for HVR Rod and Tube Resistors include  Dummy Aerial Loads, Overvoltage Protection, Capacitor Discharge and Anti Parasitic Elements in the grid and anode circuits of power valves in induction heaters.

 
 
 
 
 
 
 
 
 
 
 

Technical Specifications

TYPE

710

701

702

708*

721*

720

719

723

Do (mm)

25

25

25

20

10

10

10

10

Di (mm)

15

15

15

-

-

-

-

-

L (mm)

460

250

150

60 - 200

50 - 150

116

56

50

Lm NOM.  (mm)

25

25

25 10 10 10 10 10

WEIGHT (g)

295

160

95

38 - 130

7 - 23

18

9

7

OHMS

Min

47

22

10

4R7

10

22

10

10

Max

10000

4700

2200

4700

3300

2200

1000

1000

JOULES @ 20˚C

45000

22000

11000

4500

to

20000

1000

to

3000

2600

1100

1000

WATTS @ 20˚C

150

90

55

18 - 80

10 - 30

20

10

10

IMPULSE VOLTS

(1.2 / 50 s)

12Log R

8Log R

6Log R

3.3Log R

to

7.5LogR

1.6Log R

to

5LogR

4.3Log R

1.9Log R

1.6Log R

NOTES

At other ambients, Ta C, Watts and Joules must be multiplied by the factor (220 - Ta) / 200.

* Types 708 and 721 are available in custom lengths (see tables below).

Also Available:

50mm Diameter Tubes offering Higher Energy Absorption / Higher Average Power Rating.

25mm Diameter Tubes manufactured to custom lengths.

25mm Diameter Tubes assembled with Aluminium Ferrule Terminals.

Please contact HVR Applications Department with any specific requirements.

 

 
TYPE 708 RODS

PROD. CODE

708A

708B

708F

708D

708G

Do (mm)

20

20

20

20

20

L (mm)

70

100

125

150

185

Lm NOM.  (mm)

10

10

10 10 10

WEIGHT (g)

46

65

81

98

120

OHMS

Min

3R3

5R6

6R8

10R0

12R0

Max

1K5

2K7

3K3

3K9

5K6

JOULES @ 20˚C

5650

9050

12000

14750

18750

WATTS @ 20˚C

21

30

37.5

45

55

 
 
TYPE 721 RODS

PROD. CODE

721A

721G

721D

721B

721F

Do (mm)

10

10

10

10

10

L (mm)

60

85

100

125

150

Lm NOM.  (mm)

10

10

10 10 10

WEIGHT (g)

9

13

15

19

23

OHMS

Min

10R0

15R0

22R0

27R0

33R0

Max

4K7

6K8

10K0

12K0

15K0

JOULES @ 20˚C

1250

1900

2500

3300

4050

WATTS @ 20˚C

10

13.5

17

21.5

25.5


TERMINATIONS

Electrical Contacts

The standard electrical contacts are aluminium metallised surfaces.

Alternative metallised contacts are available in silver, brass, copper or nickel.

Corona shielded terminals are available.

Radial wire terminations are available on 10mm diameter rods.

Note :

Types 708 and 721 are available to customised lengths within the limits shown.

Custom length tubes (Do = 25mm, Di = 15mm) and larger Diamater Tubes (Do = 50mm) are also available.

ELECTRICAL PARAMETERS

Resistance Values

Preferred values are to the E6 series per decade. Other resistance values may be made available upon request.

Resistance Tolerance

20% but 10% may be made available.

Temperature Coefficient - TCR

Between - 0.8% and - 0.16% per C rise in temperature. The higher the resistivity, the higher the temperature coefficient.

Shelf Life

After 6 months storage under normal conditions the resistance change is less than 3%.

Load Life Stability

After 2000 hours continuous load producing 220 C surface temperature, the resistance change is less than 20%.

Inductance

This is negligible and the resistors may be described as Non-Inductive. In practice, the inductance of connecting leads will be greater than that of the resistor.

Voltage Coefficient

Maximum of - 5% / kV peak / cm, decreasing with resistivity.

Power Ratings

These are determined by the maximum permissible surface temperature of  220 C. In free air, vertical mounting will provide better cooling than horizontal mounting. The load ratings in the table and the de-rating formula are for vertical mounting. Forced cooling will permit a considerable increase in loading.

Environment

Air, Oil, SF6.

 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
                     
Home  |  Site Map  |  About HVR  |  Products  |  Applications  |  Agents  |  Contact Us  |  Events
   Copyright HVR International Limited 2015. All Rights Reserved. This page last updated: 17 April, 2013.