Two "copies" of a lookup table in the same query

You just need to have two "copies" of the lookup table in the query. Use table alias names to distinguish them, and column alias names to distinguish the columns in the result set.

select m.model_seq_number
     , m.boxlabel_model_desc
     , m.partnumber
     , ap1.agencypower_desc  as agencypower1
     , ap2.agencypower_desc  as agencypower2
  from model m
inner
  join agencypower ap1
    on m.agencypower_id1
     = ap1.agencypower_id
inner
  join agencypower ap2

    on m.agencypower_id2
     = ap2.agencypower_id

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