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                                                                          OMB APPROVAL
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                                  UNITED STATES                   OMB Number:   3235-0058
                       SECURITIES AND EXCHANGE COMMISSION         Expires: January 31, 2004
                             Washington, D.C. 20549               Estimated average burden
                                                                  hours per response .. 2.50
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                                   FORM 12b-25                    --------------------------
                                                                        SEC FILE NUMBER
                                                                            000-9255
                           NOTIFICATION OF LATE FILING            --------------------------
                                                                  --------------------------
                                                                       CUSIP NUMBER

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(Check One):
 [ ] Form 10-K [ ] Form 20-F [ ] Form 11-K [X] Form 10-QSB [ ] Form N-SAR

     For Period Ended:  March 31, 2002
     [ ] Transition Report on Form 10-K
     [ ] Transition Report on Form 20-F
     [ ] Transition Report on Form 11-K
     [ ] Transition Report on Form 10-Q
     [ ] Transition Report on Form N-SAR
     For the Transition Period Ended: __________________________________________


    Read attached instruction sheet before preparing form. Please print or type.

    Nothing in this form shall be  construed to imply that the  Commission  has
verified any information contained herein.

    If the  notification  relates  to a portion of the  filing  checked  above,
identify the item(s) to which the notification relates: ________________________


                                     PART I
                             REGISTRANT INFORMATION

Reliable Power Systems, Inc.
________________________________________________________________________________
Full name of registrant

Dencor Energy Cost Controls, Inc.
________________________________________________________________________________
Former name if applicable

10 South Riverside Plaza, Suite 2220
________________________________________________________________________________
Address of principal executive office (Street and number)

Chicago, Illinois 60606
________________________________________________________________________________
City, state and zip code


                                    PART II
                             RULE 12b-25(b) AND (c)

If the subject report could not be filed without unreasonable effort or expense
and the registrant seeks relief pursuant to Rule 12b-25(b), the following should
be completed. (Check box if appropriate.)

[X]  |    (a)  The reasons  described in  reasonable  detail in Part III of this
     |         form  could  not be  eliminated  without  unreasonable  effort or
     |         expense;
     |
[X]  |    (b)  The subject annual report,  semi-annual report, transition report
     |         on Form 10-K,  20-F,  11-K or Form N-SAR, or portion thereof will
     |         be filed  on or  before  the  15th  calendar  day  following  the
     |         prescribed  due  date;  or  the  subject   quarterly   report  or
     |         transition  report on Form 10-Q, or portion thereof will be filed
     |         on or before the fifth  calendar day following the prescribed due
     |         date; and
     |
[ ]  |    (c)  The  accountant's  statement  or other  exhibit  required by Rule
     |         12b-25(c) has been attached if applicable.


                                    PART III
                                   NARRATIVE

State below in reasonable detail why the Form 10-K, 11-K, 20-F 10-Q, N-SAR or
the transition report portion thereof could not be filed within the prescribed
time period. (Attach extra sheets if needed.)

     The Company has not had the opportunity to make its final review prior to
     the due date. The Company will file the Form 10-QSB by the extension date.

                                    PART IV
                               OTHER INFORMATION

(1)  Name  and  telephone  number  of  person  to  contact  in  regard  to  this
     notification

     David A. Mazur                         (720)               733-8970
     ---------------------------------------------------------------------------
         (Name)                          (Area Code)      (Telephone Number)

(2)  Have all other periodic  reports  required under Section 13 or 15(d) of the
     Securities Exchange Act of 1934 or Section 30 of the Investment Company Act
     of 1940 during the preceding 12 months or for such shorter  period that the
     registrant was required to file such report(s) been filed? If the answer is
     no, identify report(s).
                                                                 [X] Yes  [ ] No

(3)  Is it anticipated that any significant change in results of operations from
     the corresponding  period for the last fiscal year will be reflected by the
     earnings  statements  to be  included  in the  subject  report  or  portion
     thereof?
                                                                 [ ] Yes  [X] No

     If so: attach an explanation of the anticipated  change,  both  narratively
     and quantitatively, and, if appropriate, state the reasons why a reasonable
     estimate of the results cannot be made.

- --------------------------------------------------------------------------------

     Reliable Power Systems,  Inc. has caused this  notification to be signed on
its behalf by the undersigned thereunto duly authorized.

                                Reliable Power Systems, Inc.


Date: May 13, 2002              By  /s/ David A. Mazur
    -------------------            ---------------------------------------------
                                    David A. Mazur
                                    President

INSTRUCTION: The form may be signed by an executive officer of the registrant or
by any other duly authorized representative. The name and title of the person
signing the form shall be typed or printed beneath the signature. If the
statement is signed on behalf of the registrant by an authorized representative
(other than an executive officer), evidence of the representative's authority to
sign on behalf of the registrant shall be filed with the form.


                                    ATTENTION

Intentional misstatements or omissions of fact constitute Federal Criminal
Violations (see 18 U.S.C. 1001).