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Q: I need to know which contactor or starter to use to control my electric motor. ( Answered 5 out of 5 stars,   0 Comments )
Subject: I need to know which contactor or starter to use to control my electric motor.
Category: Science > Technology
Asked by: yosaimi-ga
List Price: $100.00
Posted: 20 Nov 2005 01:02 PST
Expires: 20 Dec 2005 01:02 PST
Question ID: 595370
I have Bison Right Angle gearmotor(Part Number 026-756-4605 756 Series
PSC 115V/230V Dual Voltage/Dual Frequency ) . I intend to connect it
to a contactor or a starter to get a Forward rotation,Reverse rotation
and Stop . This contactor will be controlled by PLC.
What I need is to know which  contactor or starter to use ( Brand,part
number and site  ). Also I need a very clear wiring digram to connect
the motor to the contactor.
I will be using single phase  Voltage 230V  AC  50 Hz.
The wiring diagram for the motor is available on

The motor information is available on

Can you please help me.

Request for Question Clarification by byrd-ga on 20 Nov 2005 15:33 PST
Hi yosaimi-ga,

Could you please clarify a few points?

Since you will be operating the motor in both directions, forward and
reverse, two contactors will be needed. The first contactor will apply
power to the motor and the second will determine the direction of
rotation. During rotation reversals, the PLC would control the
sequence of activation of the contactors.  For example, if the motor
was running in the forward direction and the operator selected
reverse, the PLC would automatically stop the power to the motor,
switch the direction contactor from forward to reverse, wait 2 seconds
for the motor to stop spinning, and then restart the motor.

Also, I understand that you will be using 230 VAC single-phase power
to operate your motor. In order to provide a complete wiring diagram
and specify contactors, I need to know the control voltage that will
be used between the PLC and the contactors.

In addition, I need to know which make and model of PLC you will be
using and which specific Output Module will be selected. There are
many variations in modules that will affect wiring.


Request for Question Clarification by byrd-ga on 20 Nov 2005 18:55 PST
Hi Yosaimi-ga, 

I forgot to mention that you can respond to the Request for
Clarification even while the question is locked. Looking forward to
your clarification!


Clarification of Question by yosaimi-ga on 20 Nov 2005 23:28 PST
Hi Byrd-ga,

Sorry for the delay in my Clarification. The control voltage that will
be used between the PLC and the contactors is 24V DC.
The PLC is made by SIEMENS. Model name is LOGO.The PLC Components Part
numbers are as the following :

LOGO! 230RCo 6ED1 052 - 2FB00 - 0BA5 (The logic module)
LOGO! DM16 230R 6ED1 055-1FB10-0BA0  ( Digital expansion module)
LOGO! DM8 230R 6ED1 055-1FB00-0BA1   ( Digital expansion module)

The PLC information is available on

Please let me know if you have any other questions.  

Thank you
Subject: Re: I need to know which contactor or starter to use to control my electric mo
Answered By: byrd-ga on 22 Nov 2005 18:40 PST
Rated:5 out of 5 stars
Hi Yosaimi-ga,

I'm sure you already know your request was not a simple one. But your
wiring diagram is completed. It has been saved in two formats, so you
can use one or both as you choose. Simply click on the links or
copy/paste into your browser. When the page loads, look for a link
about two-thirds of the way down the box that says, "Click here to
download ...." You will have the choice of either opening the file(s)
directly or saving them to your computer, and then opening them from
your own location.

Here is a link to a .gif image of the diagram:
*Note: this image may require scrolling to view at normal size, so you
can either zoom out to see it as a whole, or print it out. It should
print on a standard 8 1/2 x 11" paper.

And here is a .pdf version of the same diagram:
*Note: you'll need Adobe Acrobat Reader to open/view the pdf file, so
if you don't already have that, you can download a free copy here:

General purpose relays were selected for this application rather than
motor starter contactors due to the small size of the motor, i.e. 
HP. According to Bison Tech support (1-800-282-4766), the inrush
current for model 756 motor is 3.5 amps (at 230 VAC). They agreed that
interposing relays rated at or above 10 amps would be well suited for
the power and reversing circuits for the motor.

Allen-Bradley relays were chosen due to the worldwide availability of
their products. The contacts on the selected relays are rated at 15
amps and are designed for inductive loads.

Therefore, your component list is as follows: 

K1: Allen-Bradley General Purpose Relay 700-HB32A2 with relay base 700-HN154
K2: Allen-Bradley General Purpose Relay 700-HB32A2 with relay base 700-HN154

*Note: The relays listed above have a coil voltage of 230 VAC. This
voltage was selected to match the voltage that will be switched by the
specified PLC module, i.e. Siemens LOGO! 230RCo 6ED1 052 - 2FB00 -

In your clarification, however, you identified the control voltage
between the PLC and the relay as 24 VDC. If the relays' coils need to
operate on 24 VDC, then the part number for the relays K1/K2 will be
700-HB32Z24 instead of the one given above. Either way, the relay base
will be the same, i.e. 700-HN154, and the wiring diagram will not

Relay specifications can be found at:

Relay connection diagram can be found at:

Allen-Bradley-s online store is at:  However, the link does not
appear to be working.

To find a local distributor, follow this link instead:

I hope this provides you with everything you need to connect your
motor in the manner you need to. If not, or if anything is not clear,
or any links don't work, please ask for further clarification before
rating/closing your question, so I can be sure you have what you need.

Best regards,

I consulted with a professional electrical engineer of my acquaintance
who recommended and appropriately verified the suggested parts,
constructed the diagram, and let me know where to find the additional
information online.

Request for Answer Clarification by yosaimi-ga on 23 Nov 2005 03:38 PST
Hi Hi Byrd-ga,

Thank you for an outstanding job. I  guarantee you an additional tip
of: $100. Also if it is possible can you please help me with the

1- A replacement relays made by Siemens.
2- In the future if I have any other questions how can direct my
question to you.

 Once again, thank you for the great help.

Best Regards, 


Clarification of Answer by byrd-ga on 23 Nov 2005 09:05 PST
Hello Yosaimi,

You're very welcome! I'm so happy you were pleased.  

To address your additional requests:

1) The Siemens 3TX7114 series of relays will work for your
application. You will need to purchase the following items:

3TX7114-5LG13  RELAY  240 V AC DPDT 15 A
3TX7144-1E6    Socket for 3TX7114
3TX7144-1L1    Hold/eject clip for 3TX7114

Depending on whether you mount the relays on DIN rails or on a panel,
you will also need one of the following:

3TX7144-3L5    Flange adapter for 3TX7114
3TX7144-3L4    DIN adapter for 3TX7114

Relay Specifications may be found at:
Relay Wiring Details are loacted at:

To locate a Siemens distributor in your area, first go to the main
Siemens website, here: to choose your country/language. Or if
you'd like to check out online retailers, use this link instead:

The wiring diagram has been revised to match the connection
configuration of the Siemens 3TX7114 relays. Note the change in pin
numbers. If 24 VDC coil is used rather than the 230 VAC coils, replace
the relay specified above with 3TX7114-5LC03. The (+) and (-)
designations shown near the relay coils on the connection diagram are
provided for use when using the 24 VDC relays.

The revised wiring diagram is here:

2) I would be happy to work with you again. If you have additional
questions in future, and would like to direct any of them to my
attention, simply put "For Byrd-ga only" or something similar in the
subject line of your question, then proceed normally. My colleagues
will see and respect such a request. Thank you for asking.

Of course, as before, if anything isn't clear, please be sure to ask
for a clarification before rating and closing the question.

Kindest regards,

Clarification of Answer by byrd-ga on 23 Nov 2005 12:14 PST
Hello Yosaimi,
You're welcome. And thank you very much for the kind words, five star
rating and generous tip. They are most appreciated!

Best wishes,
yosaimi-ga rated this answer:5 out of 5 stars and gave an additional tip of: $100.00
Excellent answer. I appreciate it very much. Thank you.

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