×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Relay voltage specification

Relay voltage specification

Relay voltage specification

(OP)
I have the manufacturing data on several relays (coil windings, wire gauge, core type, etc.)used in elevator controls.  Is there a way to estimate the voltage they were intended to work at?

RE: Relay voltage specification

Suggestion: Please, provide more info, e.g.
1. Number of turns
2. Wire gauge
3. Wire/coil resistance for DC relay or impedance for AC relay
4. AC/DC type of relay
5. Wire type and its insulation voltage rating
6. Elevator standards, it is intended for

RE: Relay voltage specification

Please give information regarding the testing and repair of dc electronic relays.

RE: Relay voltage specification

(OP)
I am trying to find a method of calculating the operating voltage of a series of relay coils.  These relays/coils are drop in replacements for Otis Elevator controllers.  The relays are used for energizing elevator door motors, the elevator motor, releasing the elevator brake, just about everything the elevator does that is controlled by relays.  They are old technology, pre 1980’s (though the relays are new).  Otis typically used 135VDC and there might be 1 to 3 relays in series.  However, there may be some AC coils mixed in and possibly some 240V relays.

One example relay is the replacement for the Otis O21A20Y1 which uses an Otis 222CY1 coil.  The coil uses 15,310 turns of #39 gauge magnet wire with polyurethane or SFV insulation.  The resistance is 3,384 ohms +- 10%.  The wire is wound on a bobbin with a 0.773 inch outer diameter core.  This sits on a 5/8 inch E magnet iron core.  The core length is 1.498 inches and weighs about 0.148 lbs.  The main mass that it is pulling is the 1.975x1.250x0.156 armature clapper.  The clapper is made of E magnet iron.  It is pulling against a 5 oz spring.  The relay pulls the clapper a distance of 0.171 inches.  It is non-latching.

My best guess is that this is a 135VDC coil but I would like to know for sure.

RE: Relay voltage specification

Suggestion: The following could be considered:
References:
1. Giacoletto L. J. "Electronics Designers' Handbook," 2nd Edition, McGraw-Hill Book Co., 1977
2. Warrington A. R. van "Protective Relays Their Theory and Practice," Volume I, Chapman & Hall, Ltd., 1971
Relay voltage range estimation:
1. Constraint: AWG B&S Wire Gage 39 has an operating current of Idc=0.01264 Amp listed in Table 3.14, Reference 1. This implies DC voltage (assuming that the relay has a solid iron core suitable for DC magnetization/operation):
Edc=Rdc x Idc=3,384 x 0.01264=42.77VDC
2. Constraint: The DC coil imput parameters Idc and Edc must develop relay operating force greater than 5oz relay spring force.
Elementary formula for the force F, magnetic induction (flux desity), length of wire L, and current I in the coil:
F=B x I x L which has to be properly applied to the relay coil magnetic geometry.
Reference 2 indicates "pull force F" Equation (2.10) on page 2.4 as
F=(2 * (pi) * (N * Idc)**2 * A)/(x**2)
where
F=force
Pi=3.14
N=coil turns
Idc=coil current
A=pole face gap area
x=air gap at the pole center
**2=exponent 2
Take-off appropriate relay parameters and substitute them into the above formula to make sure that the Idc is adequate to develop F > 5 oz

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now
eBook - Managing the Context of Product Complexity Using the Digital Twin
Keeping track of changes to complex products is difficult—think Aerospace & Defense equipment, new generations of commercial aircraft, and software-based automobiles. A new way to managing the digital context of the physical product is required and the answer is the Digital Twin. This ebook explores the opportunity available for Operations and Maintenance for the Digital Twin. Download Now
White Paper - Trends in Industrial Filtration
Substantial progress has been made in filtration technologies in recent years. New filter media materials, designs and processes have led to filters that are more efficient, reliable, compact and longer lasting. This white paper will discuss the various trends that are impacting operational responsibilities of MROs today and the resources that are available for staying up-to-date on the latest filtration solutions. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close