Resistor Load Bank Switch Question

[Steve]

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

Thanks,
Steve

 

[D from BC]

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

Thanks,
Steve

Maybe use relays?


D from BC
British Columbia
Canada.

 

[Greg Neill]

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

What kind of resistors are involved? Too expensive
to just implement both arrangements?

 

[ehsjr]

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

Thanks,
Steve

A 4PDT will do it:

+----------------------------+
A | |
o---+---[R1]---+---------+ |
| | | |
| [R2] | |
| | | |
| o o o
| / / /
+--------o o o o o o
| | |
+------------------+ |
| | |
+--------o o |
| \ |
| o |
| | |
| [R3] |
| | |
o---+---[R4]---+---------------+
B

As drawn, the 4PDT is in the parallel position.
A and B are the connections to the "outside world".

If you can't get a 4PDT at a reasonable price,
you could use a 4PDT relay or even 2 2PDT relays.

Ed

 

[A]

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

Thanks,
Steve

A 4PDT will do it:

+----------------------------+
A | |
o---+---[R1]---+---------+ |
| | | |
| [R2] | |
| | | |
| o o o
| / / /
+--------o o o o o o
| | |
+------------------+ |
| | |
+--------o o |
| \ |
| o |
| | |
| [R3] |
| | |
o---+---[R4]---+---------------+
B

As drawn, the 4PDT is in the parallel position.
A and B are the connections to the "outside world".

If you can't get a 4PDT at a reasonable price,
you could use a 4PDT relay or even 2 2PDT relays.

Ed

Could you live with an odd number of resistors? Then you
can use a set of single throw switches:


-----+-----------+---------------+
| | |
| / /
| / /
| | |
| +---+---+ +---+---+
| | | | |
\ \ \ \ \
/ / / / /
\ \ \ \ \
/ / / / /
| | | | |
+---+---+ +---+---+ |
| | |
/ / |
/ / |
| | |
---------+---------------+-----------+


Thanks,
Alan

 

[Steve]

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

Thanks,
Steve

A 4PDT will do it:

+----------------------------+
A | |
o---+---[R1]---+---------+ |
| | | |
| [R2] | |
| | | |
| o o o
| / / /
+--------o o o o o o
| | |
+------------------+ |
| | |
+--------o o |
| \ |
| o |
| | |
| [R3] |
| | |
o---+---[R4]---+---------------+
B

As drawn, the 4PDT is in the parallel position.
A and B are the connections to the "outside world".

If you can't get a 4PDT at a reasonable price,
you could use a 4PDT relay or even 2 2PDT relays.

Ed

Could you live with an odd number of resistors? Then you
can use a set of single throw switches:


-----+-----------+---------------+
| | |
| / /
| / /
| | |
| +---+---+ +---+---+
| | | | |
\ \ \ \ \
/ / / / /
\ \ \ \ \
/ / / / /
| | | | |
+---+---+ +---+---+ |
| | |
/ / |
/ / |
| | |
---------+---------------+-----------+


Thanks,
Alan

Perfect, between both of those I can figure out a good arrangement.
How do you guys come up with these? I worked on it for some time and
didn't get very far. Thanks for the replies!
Steve

 

[Tom Bruhns]

Steve wrote:
I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?
Thanks,
Steve
A 4PDT will do it:
+----------------------------+
A | |
o---+---[R1]---+---------+ |
| | | |
| [R2] | |
| | | |
| o o o
| / / /
+--------o o o o o o
| | |
+------------------+ |
| | |
+--------o o |
| \ |
| o |
| | |
| [R3] |
| | |
o---+---[R4]---+---------------+
B
As drawn, the 4PDT is in the parallel position.
A and B are the connections to the "outside world".
If you can't get a 4PDT at a reasonable price,
you could use a 4PDT relay or even 2 2PDT relays.
Ed

Could you live with an odd number of resistors? Then you
can use a set of single throw switches:

-----+-----------+---------------+
| | |
| / /
| / /
| | |
| +---+---+ +---+---+
| | | | |
\ \ \ \ \
/ / / / /
\ \ \ \ \
/ / / / /
| | | | |
+---+---+ +---+---+ |
| | |
/ / |
/ / |
| | |
---------+---------------+-----------+

Thanks,
Alan

Perfect, between both of those I can figure out a good arrangement.
How do you guys come up with these? I worked on it for some time and
didn't get very far. Thanks for the replies!
Steve

There's another one similar to Alan's...I think I can describe it well
without resorting to ASCII-art. String (arbitrarily long) of
resistors connected in series. At each end, and at each junction
between resistors, connect the moveable contact of a SPDT-with-center-
off. Wire all the "upper" fixed switch contacts together, to one
banana jack, and wire all the "lower" fixed switch contacts together,
to another banana jack. Now you can have many possible series-
parallel combinations, including all in series (one end switch up,
other end switch down, the rest off) or all in parallel (alternating
up and down). With 10 R in series, you can go from R/10 to 10*R
resistance, with a pretty good range of resistances between.

Cheers,
Tom

 

[ehsjr]

Steve wrote:

I want to put a switch in a load bank, it is basically four resistors,
and I want to switch between the resistors being all in parallel vs
all in series. I think I've figured it out, but I need a 6 pole
Double Throw switch. There has to be an easier way to do this with a
single switch, any ideas?

A 4PDT will do it:

+----------------------------+
A | |
o---+---[R1]---+---------+ |
| | | |
| [R2] | |
| | | |
| o o o
| / / /
+--------o o o o o o
| | |
+------------------+ |
| | |
+--------o o |
| \ |
| o |
| | |
| [R3] |
| | |
o---+---[R4]---+---------------+
B

As drawn, the 4PDT is in the parallel position.
A and B are the connections to the "outside world".

If you can't get a 4PDT at a reasonable price,
you could use a 4PDT relay or even 2 2PDT relays.

Could you live with an odd number of resistors? Then you
can use a set of single throw switches:

-----+-----------+---------------+
| | |
| / /
| / /
| | |
| +---+---+ +---+---+
| | | | |
\ \ \ \ \
/ / / / /
\ \ \ \ \
/ / / / /
| | | | |
+---+---+ +---+---+ |
| | |
/ / |
/ / |
| | |
---------+---------------+-----------+

Thanks,
Alan

Perfect, between both of those I can figure out a good arrangement.
How do you guys come up with these? I worked on it for some time and
didn't get very far. Thanks for the replies!
Steve

There's another one similar to Alan's...I think I can describe it well
without resorting to ASCII-art. String (arbitrarily long) of
resistors connected in series. At each end, and at each junction
between resistors, connect the moveable contact of a SPDT-with-center-
off. Wire all the "upper" fixed switch contacts together, to one
banana jack, and wire all the "lower" fixed switch contacts together,
to another banana jack. Now you can have many possible series-
parallel combinations, including all in series (one end switch up,
other end switch down, the rest off) or all in parallel (alternating
up and down). With 10 R in series, you can go from R/10 to 10*R
resistance, with a pretty good range of resistances between.

Cheers,
Tom

Nice.


+---R---+---R---+---R---+------}}---R---+
| | | | |
| | | | |
| o-------o-------o-------o--}}-----------o---0
+---- +---- +---- +---- +----
o-------o-------o-------o--}}-----------o---0

 

[neon]

with a rotary switch all you have to do add wafers to whatever until the switch tourgue is exceeded and what kind opf power you are sitching?

 

[Steve]

Nice.


+---R---+---R---+---R---+------}}---R---+
| | | | |
| | | | |
| o-------o-------o-------o--}}-----------o---0
+---- +---- +---- +---- +----
o-------o-------o-------o--}}-----------o---0

Thanks for all the replies. I actually used a variation on this
circuit, instead of spdt switches i used spst switches, two for each
resistor, due to the amount i had on hand. Seems to work just fine,
and gives me plenty more values instead of just four resistors being
switched in parallel.

Thanks again.
Steve

 

[legg]

Thanks for all the replies. I actually used a variation on this
circuit, instead of spdt switches i used spst switches, two for each
resistor, due to the amount i had on hand. Seems to work just fine,
and gives me plenty more values instead of just four resistors being
switched in parallel.

Watch out for the ratings of the switches, if you are anticipating hot
switching, particularly for DC.

RL