Delay relay: Difference between revisions

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Several tube-era Tektronix oscilloscopes such as the [[549]], [[581]] and [[585]] contain a circuit that delays turn-on of the main supply voltages until the tubes are warmed up.
[[File:Amperite delay relays 1953.pdf|thumb|300px|right|Amperite Delay Relays, 1953 (click to enlarge)]]
Several later tube-era Tektronix oscilloscopes such as the [[549]], [[581]] and [[585]] that already use semiconductor rectifiers for the anode voltages contain a '''thermal delay relay''' such as the 6N045T or 6N030T in a circuit that delays turn-on of the main supply voltages until the tubes are warmed up.  This is normally not needed in scopes with tube rectifiers because of their inherent slow-start behavior.  


A main relay that switches the anode voltages is controlled by a '''thermal delay relay''' such as the 6N045 or 6N030 which is housed in a miniature 9-pin glass tube enclosure.
When the scope is turned on, a bi-metal strip in the delay relay is beginning to heat up.  After the delay time (30 to 60 seconds depending on the instrument), the bi-metal strip closes a contact that energizes the main relay, thereby turning the anode voltages on.  One of the main relay's contacts is used to make it self-holding, while at the same time cutting out the delay relay.  At this time, the bi-metal strip is beginning to cool so it will be ready to provide delaying turn-on again in the event of a power outage.


When the scope is turned on, a bi-metal strip in the delay relay is beginning to heat up.  After the delay time (30 to 60 seconds depending on instrument), the bi-metal strip closes a contact that energizes the main relay.  One of the main relay's contacts is used to make it self-holding while at the same time cutting out the delay relay, which is beginning to cool so it will be ready to provide delaying turn-on again in the event of a power outage.
The part number is decoded as: 6 − Heater Voltage, NO − Normally Open / C − Normally Closed, XX − delay time, T − {{B9A base}} / no suffix − {{Octal base}}).
For example, a 6NO30T is a 6 Volt filament/heating element with a normally open contact and a delay time of 30 seconds, with a miniature 9-pin base. (The original literature used NO and N0 prefixes interchangeably.)
 
{| class="wikitable"
|-
! colspan="3" | Part # reference
|- style="text-align:center;"
| Tek Part
| MFR Part
| Used in
|- style="text-align:center;"
|148-0002-00
|6NO45
|[[535]],[[545]],[[585]],[[555]]
|-
|148-0006-00
|26NO45T
|?
|-
|148-0009-00
|6NO15T
|?
|-
|148-0021-00
|6NO30T
|[[547]],[[549]]
|-
|148-0023-00
|18NO30
|[[585A]]
|}
 
==Links==
* Rajesh's time delay relay video: [https://youtu.be/ma1GSj9XWtM Part 1] / [https://youtu.be/2m3uEKUIWiA Part 2]
 
==Reference==
* [https://ia804505.us.archive.org/13/items/tek_1977_parts_price_list_number_35a/tek_1977_parts_price_list_number_35a.pdf Tektronix Parts Price List Number 35a (1977) - Page 6.053]
 
==Pictures==


<gallery>
<gallery>
6N045 1.jpg | 6N045 delay relay (from [[585]])
6N045 1.jpg | 6NO45 delay relay (from [[585]])
6N045 2.jpg | 6N045
6N045 2.jpg | 6NO45
6N045 3.jpg | 6N045
6N045 3.jpg | 6NO45
6N045 4.jpg | 6N045
6N045 4.jpg | 6NO45
Tube_18NO30.jpeg |  18NO30 (from [[585A]])
Delay relay.png | Delay relay circuit from [[581]]/[[585]]. K600 is the delay relay, K601 the main anode voltage relay.
Delay relay.png | Delay relay circuit from [[581]]/[[585]]. K600 is the delay relay, K601 the main anode voltage relay.
Amperite delay relays 1953.pdf | Data from Radio's Master, 18th Ed., 1953
Amperite delay relays 1957.pdf | Data from REPCO Radio Electronic Master Official Parts and Equipment Catalog, 21st Ed., 1957
</gallery>
</gallery>




[[Category:Electromechanical components]]
[[Category:Relays]]

Revision as of 11:52, 24 July 2021

Amperite Delay Relays, 1953 (click to enlarge)

Several later tube-era Tektronix oscilloscopes such as the 549, 581 and 585 that already use semiconductor rectifiers for the anode voltages contain a thermal delay relay such as the 6N045T or 6N030T in a circuit that delays turn-on of the main supply voltages until the tubes are warmed up. This is normally not needed in scopes with tube rectifiers because of their inherent slow-start behavior.

When the scope is turned on, a bi-metal strip in the delay relay is beginning to heat up. After the delay time (30 to 60 seconds depending on the instrument), the bi-metal strip closes a contact that energizes the main relay, thereby turning the anode voltages on. One of the main relay's contacts is used to make it self-holding, while at the same time cutting out the delay relay. At this time, the bi-metal strip is beginning to cool so it will be ready to provide delaying turn-on again in the event of a power outage.

The part number is decoded as: 6 − Heater Voltage, NO − Normally Open / C − Normally Closed, XX − delay time, T − B9A (Noval) miniature 9-pin base / no suffix − octal base). For example, a 6NO30T is a 6 Volt filament/heating element with a normally open contact and a delay time of 30 seconds, with a miniature 9-pin base. (The original literature used NO and N0 prefixes interchangeably.)

Part # reference
Tek Part MFR Part Used in
148-0002-00 6NO45 535,545,585,555
148-0006-00 26NO45T ?
148-0009-00 6NO15T ?
148-0021-00 6NO30T 547,549
148-0023-00 18NO30 585A

Links

Reference

Pictures