Ruby partial not rendering when trying to call a collection

Question

I think i'm missing something really simple...

I'm trying to call a partial (located in vdrop\_vdrops.html.erb) from another controller (in the calculators\index.html.erb view). I have variables that need to be passed back to the calculators index upon submittal for display. When I pass render partial: 'vdrops/vdrop', collection: @vdrops (see below) it just brings up the calculators index page without the partial. I am wondering if it's that I'm calling render back to the 'calculators/index' in the vdrops_controller.rb as to why I cannot get this to work properly? When I pull out the partial by itself, or call it out of it's own view, I can get it to display and submit the data back to itself and display the previously submitted data properly.

Any help is greatly appreciated!!

Here's my index code:

<div class="calculator index">
    <h2>Calculators Index Page</h2>

<%= render partial: 'vdrops/vdrop', collection: @vdrops %>

</div>

partial

<div>
    <table class="table table-condensed">

        <tr>
            <th>Item</th>
            <th>Amps</th>
            <th>Volts</th>
            <th>Distance</th>
            <th>VDrop</th>
            <th>KCMil</th>
        </tr>

  <%= form_tag ({:controller => 'Calculators', :action => 'index'}), :method => :get do %>
   Phase: <%=  select_tag :phase, options_for_select(Vdrop::PHASE_TYPE) %>
  <tr>
    <td></td>
    <td><%= number_field_tag :amps , nil %></td>
    <td><%= select_tag :volts, options_for_select(Vdrop::VOLTS_TYPE) %></td>
    <td><%= number_field_tag :distance, nil %></td>
    <td><%= number_field_tag :vdrop, nil %></td>
    <td><%= @kcmil %></td>
   </tr>
    <td></td>
    <td><%# @calc1[0]  %></td> [these are commented out because they were causing an error]
    <td><%# @calc1[1] %></td>
    <td><%# @calc1[2] %></td>
    <td><%# @calc1[4] %></td>
    <td><%# @calc1[5] %></td>
   </tr>

    </table>
     <%= submit_tag('Submit')%><br /><br />
     <%= @calc1.inspect %>
      <% end %>
</div>

Vdrops controller

class VdropsController < ApplicationController
  def index

    @amps = params[:amps].to_i
    @volts = params[:volts].to_i
    @distance = params[:distance].to_i
    @phase = params[:phase].to_i
    @vdrop = params[:vdrop].to_i

     if @phase == 1
        @kcmil = ((2 * 12.9 * @distance * @amps) / @vdrop).round(2)
      else
        @kcmil = ((1.73205080756887 * 12.9 * @distance * @amps) / @vdrop).round(2)
      end
      @calc1 = [@amps, @volts, @distance, @phase, @vdrop, @kcmil]
     render "calculators/index"
  end

end